Exercise 11 Page 442

Use the fact that the sum of angle measures in a quadrilateral is 360.

Equation: x+115+65+115=360
Missing Measure: 65^(∘)

Practice makes perfect

We want to write and solve an equation to find the missing measure x in the given quadrilateral.

To do this, we can use the fact that the sum of the measures of the angles of a quadrilateral is 360^(∘). Let's use this fact to write an equation by adding the given measures and setting the sum equal to 360. x+ 115+ 65+ 115=360 Now, let's solve the equation for x.

x+115+65+115=360

AddTerms

Add terms

x+295=360

SubEqn

LHS-295=RHS-295

x+295-295=360-295

SubTerms

Subtract terms

x=65

The missing measure is 65^(∘).