Question

What’s the value of a?

Answer 1

A= 69 degrees

Explanation:

if all those angles equal a total of 180 degrees then all you need to do is add the angles your given which in this case is 21 and a 90 degree angle which would equal 111 degrees, then subtract 111 from 180 and that would be the answer to the missing angle, which is 69 degrees.

21 + 90 = 111

180- 111 = 69

Answer 2

a = 69

Explanation:

The linear pair equals 180 degrees.

a + 90 + 21 = 180

a + 111 = 180

a = 69

nice!