Exercise 10 Page 394

We want to find the measures of the angles in the given triangle.

To find these angle measures, we will first recall a key piece of information!

Angle Sum of a Triangle
The sum of the measures of the interior angles of a triangle is $18 0^{\circ} .$

With this rule, we can write an equation connecting the measures of the angles of our triangle.

x^{\circ} + 12 0^{\circ} + x^{\circ} = 18 0^{\circ}

Let's solve the equation and find the value of

x .

For simplicity, we will not write the degree symbol.

x + 120 + x = 180

▼

Solve for

x

Add terms

2 x + 120 = 180

$LHS - 120 = RHS - 120$

2 x = 60

$LHS / 2 = RHS / 2$

x = 30

The measure of both of the missing angles is

3 0^{\circ} .