Question

Find the measure of angle a. angle a = ?°

Answer 1

$140 + 25 = 165 \\ 180 - 165 = 15$
so a is 15

Answer 2

Since the sum of the interior angles of every triangle is 180 degrees, you can subtract the two known interior angle values from 180 to find the measure of the third interior angle.

180 - 140 - 25 = a

Subtract.

15 = a

Find the sum to check work.

140 + 25 + 15 ? 180

165 + 15 ? 180

180 = 180

Answer:

m∠a = 15°