Exercise 1 Page 211

We have been given the measures of the two angles of a triangle, 57 and 101. We will find the measure of the third angle using the Triangle Angle-Sum Theorem. This theorem tells us that the measures of the interior angles of a triangle must add to 180^(∘).

If we let x be the unknown measure of the third angle, we can create an equation to solve for the third angle.

57+ 101+ x=180

AddTerms

Add terms

158+x=180

SubEqn

LHS-158=RHS-158

x=22

The measure of the third angle is 22^(∘).