Exercise 1 Page 392

We want to find the measure of the angle in the given triangle.

To find this angle measure, we will first recall a key piece of information!

With this rule, we can write an equation connecting the measures of the angles of our triangle. x^(∘)+ 75^(∘)+ 60^(∘)=180^(∘) Let's solve the equation and find the value of x. For simplicity, we will not write the degree symbol.

The measure of the third angle is 45^(∘).