Exercise 68 Page 56

We have two adjacent angles and we want to find the measure of their sum. We can demonstrate relationship between measures of given angles and the one we want to find with an equation. m∠ SQP + m∠ PQR= m∠ RQS We know that m∠ PQR=60 and from the picture we can deduce that m∠ SQP=90, because this angle is denoted with a square near the vertex. We can find m∠ RQS by substituting those values into the equation.

m∠ SQP + m∠ PQR= m∠ RQS

SubstituteII

m∠ SQP= 90, m∠ PQR= 60

90+ 60= m∠ RQS

AddTerms

Add terms

150= m∠ RQS

RearrangeEqn

Rearrange equation

m∠ RQS=150

The measure of ∠ RQS is 150.