How can we help?

You can also find more resources in our Help Center.

Triangle

Equilateral Triangle

Scalene Triangle

Isosceles Triangle

A Polygon with 3 sides. The point of intersection of 2 sides…

A Triangle with 3 congruent sides.

A Triangle with 3 sides that have different lengths.

A Triangle with at least 2 congruent sides.

Triangle

A Polygon with 3 sides. The point of intersection of 2 sides…

Equilateral Triangle

A Triangle with 3 congruent sides.

triangle

vertex

Angles of a triangle are labeled 3 ways:

The sum of the measures of the interio…

3 sided polygon

A common endpoint of two sides of a polygon or an angle.

Three capital letters that name the angle... A capital letter th…

180 degrees

triangle

3 sided polygon

vertex

A common endpoint of two sides of a polygon or an angle.

Acute Triangle

Equiangular Triangle

Obtuse Triangle

Right Triangle

If all three of the angles of a triangle are acute angles, th…

If all three angles of an acute triangle are congruent, then…

If one of the angles of a triangle is an obtuse angle, then t…

If one of the angles of a triangle is a right angle, then the…

Acute Triangle

If all three of the angles of a triangle are acute angles, th…

Equiangular Triangle

If all three angles of an acute triangle are congruent, then…

Midsegment

Point of Concurrency

Median

Centroid

A segment that connects the midpoints of two sides of a trian…

The point where three or more lines, segments, or rays inters…

A median is a segment that connects the vertex of a triangle…

The point of concurrency for three medians.

Midsegment

A segment that connects the midpoints of two sides of a trian…

Point of Concurrency

The point where three or more lines, segments, or rays inters…

triangle

vertex

Angles of a triangle are labeled 3 ways:

The sum of the measures of the interio…

3 sided polygon

A common endpoint of two sides of a polygon or an angle.

Three capital letters that name the angle... A capital letter th…

180 degrees

triangle

3 sided polygon

vertex

A common endpoint of two sides of a polygon or an angle.

If all three of the angles of a triang…

If all three angles of an acute triang…

If one of the angles of a triangle is…

If one of the angles of a triangle is…

Acute Triangle

Equiangular Triangle

Obtuse Triangle

Right Triangle

If all three of the angles of a triang…

Acute Triangle

If all three angles of an acute triang…

Equiangular Triangle

triangle

vertex

Angles of a triangle are labeled 3 ways:

The sum of the measures of the interio…

3 sided polygon

A common endpoint of two sides of a polygon or an angle.

Three capital letters that name the angle... A capital letter th…

180 degrees

triangle

3 sided polygon

vertex

A common endpoint of two sides of a polygon or an angle.

SSS

SAS

ASA

AAS

Three sides of one triangle are congruent to three sides of a…

Two sides and the included angle of one triangle are congruen…

Two angles and the included side of one triangle are congruen…

Two angles and the non-included side of one triangle are cong…

SSS

Three sides of one triangle are congruent to three sides of a…

SAS

Two sides and the included angle of one triangle are congruen…

Acute Scalene

Right

Obtuse Scalene

Acute

all three angles are less than 90 degrees and all three angle…

one angle is exactly 90 degrees

one angle is over 90 degrees and all three angles are different

all three angles are less than 90 degrees

Acute Scalene

all three angles are less than 90 degrees and all three angle…

Right

one angle is exactly 90 degrees

Point of Concurrency

Circumcenter

Circumscribed

Incenter

an intersection of 2 lines. NEVER leaves a gap at intersection

point of concurrency of a perpendicular bisector

the name of the circle after you identify the circumcenter

point of concurrency of angle bisector

Point of Concurrency

an intersection of 2 lines. NEVER leaves a gap at intersection

Circumcenter

point of concurrency of a perpendicular bisector

If all three of the angles of a triang…

If all three angles of an acute triang…

If one of the angles of a triangle is…

If one of the angles of a triangle is…

Acute Triangle

Equiangular Triangle

Obtuse Triangle

Right Triangle

If all three of the angles of a triang…

Acute Triangle

If all three angles of an acute triang…

Equiangular Triangle

If three sides in a triangle are congr…

If two sides and an included angle in…

If two angles and an included side in…

If two angles and a side that is not i…

SSS (Side Side Side)

SAS (Side Angle Side)

ASA (Angle Side Angle)

AAS (Angle Angle Side) Theorem

If three sides in a triangle are congr…

SSS (Side Side Side)

If two sides and an included angle in…

SAS (Side Angle Side)

triangle

equilateral triangle

isosceles triangle

scalene triangle

A figure formed by three segments joining at three points not…

A triangle with three congruent sides

A triangle that has 2 equal sides.

a triangle with no congruent sides

triangle

A figure formed by three segments joining at three points not…

equilateral triangle

A triangle with three congruent sides

Midsegment

Point of Concurrency

Median

Centroid

A segment that connects the midpoints of two sides of a trian…

The point where three or more lines, segments, or rays inters…

a segment that connects the vertex of a triangle with the mid…

The point of concurrency for three medians.

Midsegment

A segment that connects the midpoints of two sides of a trian…

Point of Concurrency

The point where three or more lines, segments, or rays inters…

Isosceles Triangle

Equilateral Triangle

Scalene Triangle

Right Triangle

At least 2 sides and 2 interior angles but must be congruent.

All sides and interior angles are congruent and 60 degrees.

No sides and angles are congruent. They all have different me…

It includes one 90 degrees angle.

Isosceles Triangle

At least 2 sides and 2 interior angles but must be congruent.

Equilateral Triangle

All sides and interior angles are congruent and 60 degrees.

midsegment

perpendicular bisector

angle bisector

median

connects two midpoints of a triangle; is 1/2 the size of para…

A line that is perpendicular to a segment at its midpoint.

Ray/segment/line that intersects an angle at the vertex and c…

a segment whose endpoints are a vertex of a triangle and the…

midsegment

connects two midpoints of a triangle; is 1/2 the size of para…

perpendicular bisector

A line that is perpendicular to a segment at its midpoint.

triangle

vertex

Angles of a triangle are labeled 3 ways:

The sum of the measures of the interio…

3 sided polygon

A common endpoint of two sides of a polygon or an angle.

Three capital letters that name the angle... A capital letter th…

180 degrees

triangle

3 sided polygon

vertex

A common endpoint of two sides of a polygon or an angle.

Vertex angle

Exterior

A right triangle

Complementary

Non congruent angle of an isosceles triangle

The __________ of a triangle is the sum of the remote interio…

Before you can use HL in a proof, you must state that you have

The two acute angles of a right triangle are

Vertex angle

Non congruent angle of an isosceles triangle

Exterior

The __________ of a triangle is the sum of the remote interio…

If all three of the angles of a triang…

If all three angles of an acute triang…

If one of the angles of a triangle is…

If one of the angles of a triangle is…

Acute Triangle

Equiangular Triangle

Obtuse Triangle

Right Triangle

If all three of the angles of a triang…

Acute Triangle

If all three angles of an acute triang…

Equiangular Triangle

Right Triangle

Pythagorean Theroem

Hypotenuse

Legs

One right angle

a squared + b squared = c squared... a^2 + b^2 = c^2

Longest leg across from rt. angle (c)

Two shorter sides of a rt. triangle (a & b)

Right Triangle

One right angle

Pythagorean Theroem

a squared + b squared = c squared... a^2 + b^2 = c^2

perpendicular bisector

point of concurrency of perpendicular…

angle bisector

point of concurrency of angle bisector

segment, ray, line, or plane that's perpendicular to a segmen…

circumcenter

if a point lies on the bisector angle, then it's equidistant…

incenter

perpendicular bisector

segment, ray, line, or plane that's perpendicular to a segmen…

point of concurrency of perpendicular…

circumcenter

Inscribed Circle

Incenter of a Triangle

Altitude of a Triangle

In an Accute triangle the angle is ___…

If the sides of the polygon are tangent to the circle. It is…

The point of concurrency of the angle bisector of a triangle.

The perpindicular segment from a vertex to the line containin…

Inside

Inscribed Circle

If the sides of the polygon are tangent to the circle. It is…

Incenter of a Triangle

The point of concurrency of the angle bisector of a triangle.

triangle

vertex

Angles of a triangle are labeled 3 ways:

The sum of the measures of the interio…

3 sided polygon

A common endpoint of two sides of a polygon or an angle.

- Three capital letters that name the angle... - A capital lett…

180 degrees

triangle

3 sided polygon

vertex

A common endpoint of two sides of a polygon or an angle.

Triangle in equality Theorem

Right triangle

Obtuse triangle

Equiangular triangle

The sum of the lengths of any two sides of a triangle must be…

1 right angle

I obtuse triangle

3 congruent acute angles

Triangle in equality Theorem

The sum of the lengths of any two sides of a triangle must be…

Right triangle

1 right angle

Right Triangle

Acute Triangle

Obtuse Triangle

Equilateral Triangle

a triangle with 1 right angle

a triangle where all 3 angles are acute

a triangle that has 1 obtuse angle

a triangle with 3 congruent sides and 3 congruent angles

Right Triangle

a triangle with 1 right angle

Acute Triangle

a triangle where all 3 angles are acute

third angle theorem

exterior angle theorem

triangle sum theorem

add up to one 180

if two angles of one triangle are congruent to two angles of…

<1+<2=<4 , 2 inside angles add up to outside angle

<1 + <2 +<3 = 180

- vertical angles... - same side interior angles... - supplemetary…

third angle theorem

if two angles of one triangle are congruent to two angles of…

exterior angle theorem

<1+<2=<4 , 2 inside angles add up to outside angle

Isosceles Triangle

Obtuse Triangle

Obtuse angle

Right Triangle

A triangle with at least two congruent side

A triangle with one obtuse angle.

An angle that measure more than 90 degrees

A triangle with one right angle

Isosceles Triangle

A triangle with at least two congruent side

Obtuse Triangle

A triangle with one obtuse angle.

CPTC

sss

sas

asa

Corresponding Parts of Congruent Triangles are Congruent

3 pairs of congruent sides

-2 pairs of congruent sides... -1 pair includes congruent angels

-2 pairs of congruent angels... -1 pair of congruent sides

CPTC

Corresponding Parts of Congruent Triangles are Congruent

sss

3 pairs of congruent sides

triangle

isosceles triangle

scalene triangle

acute triangle

a figure formed by three segments joining three non- collinea…

has at least two congruent sides

has no congruent sides

has three acute angles

triangle

a figure formed by three segments joining three non- collinea…

isosceles triangle

has at least two congruent sides

Circumcenter

Incenter

Inscribed

Circumscribed

The point of concurrency where the perpendicular bisectors of…

The point of concurrency where the angle bisectors of a trian…

A circle touches each side of a polygon in exactly one point.

A circle touches each vertex of a polygon in exactly one point.

Circumcenter

The point of concurrency where the perpendicular bisectors of…

Incenter

The point of concurrency where the angle bisectors of a trian…

Midsegment of a Triangle

Concurrent

Altitude of a Triangle

Angle Bisector of a Triangle

The segment joining the midpoints of two sides of a triangle.…

Three or more lines are called concurrent if they all meet at…

The height. The segment from a vertex. The ________ are alway…

The ray from a vertex such that it cuts the angle into two eq…

Midsegment of a Triangle

The segment joining the midpoints of two sides of a triangle.…

Concurrent

Three or more lines are called concurrent if they all meet at…

circumcenter of a triangle

incenter of a triangle

altitude of a triangle

orthocenter of a triangle

perpendicular bisectors from every triangle side

when all three angles of a triangle are bisected

is a perpendicular segment from a vertex to the line containi…

the point of concurrency of the three altitudes of a triangle

circumcenter of a triangle

perpendicular bisectors from every triangle side

incenter of a triangle

when all three angles of a triangle are bisected

POLYGON

TRIANGLE

EQULATERAL TRIANGLE

ISOSCELES TRIANGLE

A CLOSED PLANE FIGURE MADE UP OF LINE SEGMENTS WITH 3 OR MORE…

A POLYGON WITH 3 SIDES AND 3 ANGLES

A TRIANGLE WITH 3 CONGRUENT SIDES

A TRIANGLE WITH 2 CONGRUENT SIDES

POLYGON

A CLOSED PLANE FIGURE MADE UP OF LINE SEGMENTS WITH 3 OR MORE…

TRIANGLE

A POLYGON WITH 3 SIDES AND 3 ANGLES

circumcenter

incenter

centroid

median

point of congruency of the perpendicular bisectors of a trian…

the point of concurrency of the angle bisectors of a triangle

point of concurrency of the medians, it is always inside the…

a segment whose endpoints are a vertex and the midpoint of th…

circumcenter

point of congruency of the perpendicular bisectors of a trian…

incenter

the point of concurrency of the angle bisectors of a triangle

circumcenter of a triangle

circumscribed about

concurrent

incenter of a triangle

The point of concurrency of the three perpendicular bisectors…

happens to a circle when the vertices of a polygon lie on the…

happening at the same time; parallel

The point of concurrency of the three angle bisectors of a tr…

circumcenter of a triangle

The point of concurrency of the three perpendicular bisectors…

circumscribed about

happens to a circle when the vertices of a polygon lie on the…

Side-Side-Side (SSS) Postulate

Side-Angle Side (SAS) Postulate

Third Angles Theorem

Angle-Side-Angle (ASA) Postulate

If three sides of one triangle are congruent to the three sid…

If two sides and the included angle of one triangle of one tr…

If two angles of one triangle are congruent to two angles of…

If two angles and the included side of one triangle are congr…

Side-Side-Side (SSS) Postulate

If three sides of one triangle are congruent to the three sid…

Side-Angle Side (SAS) Postulate

If two sides and the included angle of one triangle of one tr…