Geometry - Section 1.5

ANGLE BISECTOR

a ray that cuts an angle in half

ACUTE ANGLE

an angle that measures less than 90

OBTUSE ANGLE

angle measure greater than 90 but less than 180

STRAIGHT ANGLE

angle measure of 180

RIGHT ANGLE

angle measure of 90

CONGRUENT ANGLES

angles with equal measures

ANGLE ADDITION POSTULATE

one small angle + another small angle = big angle

ANGLE

opposite rays that share a common endpoint

VERTEX OF AN ANGLE

where the two legs of an angle intersect

INTERIOR OF AN ANGLE

"inside" of the angle

EXTERIOR OF AN ANGLE

"outside" of the angle