Question

Find the measure of angle A.

110°
O 80°
O 105°
O 30°
O100°
14 + 6x
A
3x-3

Answer 1

`80^(\circ)`

Explanation:

The interior angles of the triangle are
`70^(\circ), (14+6x)^(\circ)`, and
`(3x-3)^(\circ)`.

Angles in a triangle add to
`180^(\circ)`.

`70+14+6x+3x-3=180 \\ \\ 81+9x=180 \\ \\ 9x=99 \\ \\ x=11`

So,
`m\angle A=14+6(11)=80^(\circ)`.