1. Objectives Name and classify angles.
Measure and construct angles and angle
bisectors.

2. Vocabulary angle right angle vertex obtuse angle
interior of an angle straight angle
exterior of an angle congruent angles
measure angle bisector
degree
acute angle

3. You can name an angle several ways: by its vertex,
__________ – a figure formed by two rays, or sides, with a common endpoint called the __________ (plural: __________ ).
You can name an angle several ways:
by its vertex,
by a point on each ray and the vertex, or
by a number.
ray
vertex

4. __________, __________ , __________ , or __________
____________________– the set of all points between the sides of the angle.
____________________ – the set of all points outside the angle.
Angle Name
__________, __________ , __________ , or __________
You cannot name an angle just by its vertex if the point is the vertex of more than one angle. In this case, you must use all three points to name the angle, and the middle point is always the vertex.

5. Example 1
Write the different ways you can name the angles in the diagram.

7. Example 2
Find the measure of each angle. Then classify each as acute, right, or obtuse.
A. WXV
B. ZXW

8. mABC = mDEF, so ABC  DEF.
____________________ are angles that have the same measure.
mABC = mDEF, so ABC  DEF.
This is read as “angle ABC is congruent to angle DEF.”
__________ are used to show that the two angles are congruent.

9. Example 3
mXWZ = 121° and mXWY = 59°. Find mYWZ.

10. An _______________is a ray that divides an angle into two congruent angles.
JK bisects LJM; thus LJK  KJM.

11. Example 4a
KM bisects JKL, mJKM = (4x + 6)°, and mMKL = (7x – 12)°. Find mJKM.

12. Example 4b
Find the measure of each angle.
QS bisects PQR, mPQS = (5y – 1)°, and
mPQR = (8y + 12)°. Find mPQS.