Exercise 3 Page 413

Because the angles in the given diagram are on opposite sides of an intersection of two lines, we know that they are vertical.

Since the angles are supplementary, we know that their measures should be equal. We can solve for x by creating an equation using the values of the angles. Let's ignore the symbol ^(∘) for a moment.

x+10 = 59

SubEqn

LHS-10=RHS-10

x+10 -10= 59-10

SubTerm

Subtract term

x= 49

We found that the given pair of angles are vertical and the value of x is 49^(∘).