Write and Solve Equations using Geometry Concepts

An isosceles triangle has base angles that each measure 42 degrees. Which equation can be used to find z, the measure of the third angle in the isosceles triangle in degrees?

• 84 + 2z = 180

• 84 + z = 180

• 42 + 2z = 180

• 42 + z = 180

The angle measures of a triangle are shown in the diagram.

What is the value of x?

• 25

• 20

• 10

• 28

Mathematical Equivalence

ON

• 77 = 5x + 18

• 77 + (5x + 18) = 180

• 77 + (5x + 18) = 90

• 77 + (5x + 18) = 360

The angle measures of a triangle are shown in the diagram.

What is the value of x?

Mathematical Equivalence

ON

The perimeter of a rectangle is 32 inches.

-The rectangle has a width of 4 inches

-The rectangle has a length of 2.5x inches

Which equation can be used to find the value of x?

• 4 + 2.5x = 32

• 8 + 5x = 32

• 4(2.5x) = 32

• 8(5x) = 32