1.3 Angles and Their Measures 4. 5x + 2 = 8x – 10

Name and classify angles. Measure and construct angles and angle bisectors. Objectives 1.3 Angles and Their Measures

angle is a figure formed by two ______, or sides, with a common _____________ called the vertex (plural: vertices). R,R, Angle Name SRT,TRS,or 1 You cannot name an ______ just by its ______ if the point is the vertex of more than ____ _______. In this case, you must use all _____ _______ to name the angle, and the _______ point is always the vertex. angle vertex one threepoints middle angle rays endpoint

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

Classify each angle as acute, right, or obtuse. A. XTS B. WTU C. XTU Example 2

Example 3 Find the measure of each angle.

Use a protractor to draw an angle with a measure of 165°. Example 4

Find the measure of each angle. Then classify each as acute, right, or obtuse. Example 5 C. WXV B. ZXW A. YXW

Example 6 Find the measure of each angle. Then classify each as acute, right, or obtuse. C. COD B. BOCA. AOB D. DOB

Congruent angles are angles that have the same ___________. Arc marks are used to show that the two angles are congruent. measure In the diagram, mABC = mDEF, so ABC  DEF.

mDEG = 115°, and mDEF = 48°. Find mFEG Example 7

Example 8 K is in the interior of LMN, mLMK =52°, and mKMN = 12°. Draw the picture. Find mLMN.

An angle bisector is a _____ that divides an angle into ____ _________ ______. ray two congruent angles

Example 9

Example 10

Example 11

Example 12