Exercise 35 Page 404

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

To find this angle measure, 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} + 6 3^{\circ} + 9 0^{\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 + 63 + 90 = 180

▼

Solve for

x

Add terms

x + 153 = 180

$LHS - 153 = RHS - 153$

x = 27

The measure of the missing angle is

2 7^{\circ} .