Do Now Classify each angle as acute right

Do Now Classify each angle as acute, right, obtuse or straight. 1. m ˂ DBE = 35 ° 2. m ˂ EBC = 80° 3. m ˂ MPL = 90° 4. m ˂ ABD = 180 ° 5. m ˂ CRF= 91 °

Geometry 1. 5: Describe Angle Pair Relationships Objective: SWBAT use special angle relationships to find angle measures.

Angle Relationships n Complementary Angles: n n Two angles whose measures have a sum of 90° Supplementary Angles: n Two angles whose measures have a sum of 180°

Example For each number below, Angles 1 and 2 are complementary and angles 2 and 3 are supplementary. Find the missing angles. measure.

Supplementary & Complimentary Angles Examples

Angle Relationships n Adjacent Angles: n n Angles that share a common vertex and side but have no common interior points Linear Pair: n Two adjacent angles whose non-common sides are opposite rays. The sum of the measures of angles that form a linear pair is 180°

Angle Relationships n Vertical Angles: n * n Two angles whose sides form two pairs of opposite rays vertical angles are congruent * Perpendicular Lines: n Two lines that intersect to form a right angle.

Find angle measures in a linear pair ALGEBRA Two angles form a linear pair. The measure of one angle is 5 times the measure of the other. Find the measure of each angle. SOLUTION Let x° be the measure of one angle. The measure of the other angle is 5 x°. Then use the fact that the angles of a linear pair are supplementary to write an equation.

Vertical? Linear? Neither?

Vertical Angles

Homework Textbook Pages 39 - 40 # 10, 14, 17, 20, 22, 24, 26, 31, 40, 42