Answer:
Choice A. 15
Explanation:
Solution:
In the given figure we can see two adjacent angles on a right angle. (30° and 4x)
We know that a right angle is an angle of exactly 90° .
∴ 30 + 4x = 90
⇒4x = 90 -30
⇒x = 60/4
⇒x = 15
Verification:
30 + 4x = 90
⇒30 + 4×15 = 90
⇒30 + 60 = 90
⇒90 = 90