Geometry terms

25 terms

If two lines form congruent adjacent angles, then the

lines are perpendicular

if the exterior sides of two adjacent acute angles are perpendicular, than

the angles are supplementary

if two angles are complements of congruent angles ( or the same angle) then the

two angles are congruent

parallel

The measure of an exterior angle of a triangle equals...

the sum of the measures of the two remote interior angles

If a point lies on the perpendicular bisector of a segment, then the point is

equidistant from the endpoints of the segment

If a point is equidistant from the endpoints of a segment then the point

lies on the perpendicular bisector of the segment

If a point lies on the bisector of an angle then the point

is equidistant from the sides of the angle

If a point is equidistant from the sides of an angle, then the

point lies on the bisector of the angle

If three parallel lines cut off congruent segments on one transversal, then they

cut off congruent segments on every transversal

perpendicular

each diagonal of a rhombus bisects

two angles of the rhombus

Th midpoint of the hypotenuse of a right triangle is

equidistant from the three vertices

If one side of a triangle is longer than a second side,

then the side opposite the first angle is longer than the sie opposite the second angle

If an angle of one triangle is congruent to an angle of another triangle and the sides including those angles are in proportion, then the triangles are similar

SAS similarity theorem

If the sides of two triangles are in proportion, then the triangles are similar

SSS similarity theorem

If a line parallel to one side of a triangle intersects the other two sides, then it divides those sides proportionally

Triangle Proportionality theorem

Corollary 1

Corollary 2

A diameter that is perpendicular to a chord

bisects the chord and its arc

In the same circle or in congruent circles

chords equally distant from the center (or centers) are congruent and congruent chords are equally distant from the center (or centers)

The measure of an angle formed by two chords that intersect inside a circle is

equal to half the measure of the sum of the intercepted arcs

the measure of an angle formed by two secants, two tangents or a secant and a tangent drawn from a point outside a circle is

equal to half the difference of the measures of the intercepted arcs.