1. Lesson 2 Solve for Unknown Angles using Equations

2. Lesson Objective: I will solve for unknown angles in word problems and in diagrams involving complementary, supplementary, vertical, and adjacent angles.

3. Two lines meet at a point. In a complete sentence, describe the relevant angle relationships in the diagram. Find the values of r, s, and t.

4. < r is adjacent to < s < r is supplementary to < 25 < r is vertical to < t Plus many more….

5. Lesson Summary: To solve problems involving angles, I must follow these steps: 1)Identify the angle relationship 2)Set up an equation 3)Solve for the unknown value 4)Check answer by substitution

6. Two lines meet at the vertex of a ray. In a complete sentence, describe the relevant angle relationships in the diagram. Set up and solve an equation to find the value of p and r.

7. Solution  A supplementary angle is created with 28°, 16° and p°= 180°  Equation: 28+16+p=180 44+p=180 p=136

8. Three lines meet at a point. In a complete sentence, describe the relevant angle relationships in the diagram. Set up and solve an equation to find the value of z.

9. Solution  Angle z and an angle = 90° which is a complementary angle  The unknown angle is 19° because it is an opposite vertical angle to a known measured angle.  Thus, 90-19=z  71=z  The angle measurement of z=71°

10. Two lines meet at the vertex of a ray. The ray is perpendicular to one of the lines as shown. In a complete sentence, describe the relevant angle relationships in the diagram. Set up and solve an equation to find the value of t.

11. Solution  The angles are supplementary which means the total of all angles will = 180°  From the diagram, we can see that one angle is 90° and one angle is 26°  Thus our equation is 180=90+26+x  Solve for our variable 180=116+x 64=x Now, we must find the measurement of t which 180-64=116 The measurement of angle t=116° x°

12. Solving Angle Steps: To solve problems involving angles, I must follow these steps: 1)Identify the angle relationship 2)Set up an equation 3)Solve for the unknown value 4)Check answer by substitution