Question

8. Solve for y. **THINK! a) what type of angles do you have? b) what is their

relationship (add up to 90, add up to 180, or congruent)? c) set up an equation
and solve *

Answer 1

a. Linear pair (supplementary)

b. Add up to 180°

c.
`y = 20`

Explanation:

78° and (5y + 2)° are a linear pair. They are supplementary, and add up to 180°.

Therefore, the following equation expresses their relationship:

`78 + (5y + 2) = 180`

Solve for y

`78 + 5y + 2 = 180`

`78 + 2 + 5y = 180`

`80 + 5y = 180`

Subtract 80 from both sides

`80 + 5y - 80 = 180 - 80`

`5y = 100`

Divide both sides by 5

`(5y)/(5) = (100)/(5)`

`y = 20`