How can we help?

You can also find more resources in our Help Center.

30-60-90 Special Right Triangle

a, 2a, a√3

45-45-90 Special Right Triangle

a, a, a√2

Polygon

closed, 2D figure whose sides are segments (straight) and intersect only at their end points (vertex; vertices)

Trapezoid

a quadrilateral with exactly one set of parallel sides

Parallelogram

a quadrilateral with exactly two sets of parallel sides

Rhombus

a parallelogram with four congruent sides (not necessarily 90° angles)

Square

a quadrilateral with two sets of equal sides and four 90° angles

Rectangle

a quadrilateral with two sets of equal sides and four 90° angles

5 sided polygon

pentagon

6 sided polygon

hexagon

7 sided polygon

heptagon

8 sided polygon

octagon

9 sided polygon

nonagon

N-sided polygon

n-gon

Area

measurement of space inside a figure

Area of a Parallelogram

Area=base x height

Area of a Trapezoid

(only 1 set of parallel lines) A=(b1+b2/2)h

Circumference (definition)

measurement around circle

Circumference (formula)

circumference=diameter x ∏ (pi)

Area of a circle

A=∏(r2)

Prism

has 2 congruent bases that are parallel (can be any polygon) All remaining faces (sides) are rectangles

Cylinder

a solid with 2 congruent circular bases that are parallel to each other

Surface area (S.A.)

the sum of the areas of the faces of a solid

Area of a triangle

A=1/2 bh

Pythagorean Theorem

a2+b2=c2

Equilateral

congruent sides and angles

Isosceles Triangle

has 2 congruent sides

Scalene Triangle

has NO congruent sides

Acute

<90°

Right Angle

exactly 90°

Obtuse

>90°

Perimeter

the sum of the measurements of each face of a polygone