WarmUp Exercises Classify each angle as acute obtuse

Warm-Up Exercises Classify each angle as acute, obtuse, or right. 1. 90º 2. 72º 3. 116º 4. How do you know that ~ 1= 2? 2 1

Warm-Up EXAMPLE 2 Exercises a triangle a coordinate Example 1 Classify (a): Found on pagein 208 in the book plane Classify PQO by its sides. Then determine if the triangle is a right triangle. STEP 1 Use the distance formula to find the side lengths.

Warm-Up 2 Exercises EXAMPLE Classify a triangle in a coordinate plane STEP 2 Check for right angles.

for Examples 1 and 2 Warm-Up Exercises Example 1 (b) GUIDED PRACTICE Triangle ABC has the vertices A(0, 0), B(3, 3), and C( – 3, 3). Classify it by its sides. Then determine if it is a right triangle.

Warm-Up Try on. Exercises your own! A triangle has the given vertices. Graph the triangle and classify it By its sides. Then determine if it is a right triangle. A (2, 3), B (6, 3), C (2, 7)

Warm-Up Exercises Important Theorems THEOREM 4. 1: Triangle Sum Theorem The sum of the measures of the interior angles of a triangle is 180°. THEOREM 4. 2: Exterior Angle Theorem The measure of an exterior angle of a triangle is equal to the sum of the measures of the two nonadjacent interior angles.

Warm-Up EXAMPLE 3 Exercises Example 2 Find (a) Found onmeasure page 209 an angle Find m JKM. STEP 1 Write and solve an equation to find the value of x. STEP 2 Plug it in!

More Examples of Using Triangle Angle Sum Theorem and Warm-Up Exercises Exterior Angle Theorem Find the value of x. Then classify the triangle by its angles. 1. 2.

Warm-Up Exercises Try these your own! foron. Examples 3 and 4 GUIDED PRACTICE 1. Find the measure of 1 in the diagram shown. 2. Find the value of x and then find the measure of each angle. 3. Find the measure of each interior angle of ABC, where m A = x ° , m B = 2 x° , and m C = 3 x°.

Warm-Up Exercises. COROLLARY Corollary: A statement that can be proved easily using a theorem. Corollary to the Triangle Sum Theorem The acute angles of a right triangle are complementary.

Warm-Up 4 Exercises EXAMPLE Find. Example angle measures 3: Page from 210 a verbal description Step 1: Use the corollary to set up and solve an equation.

Warm-Up Exercises Tryfor on Examples your own! 3 and 4 GUIDED PRACTICE Find the measures of the acute angles of the right triangle in the diagram shown. What is the measure of the obtuse angle formed between the staircase and a segment extending from the horizontal leg? A 2 x B x C Q