What is the value of h? 
h = 1.5°, h = 9°, h = 10°, h = 13.5°

Solution:

From the figure,

The angles (3h + 18)° and (15h)° are supplementary.

Sum of supplementary angles = 180°

3h + 18° + 15h = 180°

By further calculation, we get

18h + 18° = 180°

So we get,

⇒ h + 1° = 10°

⇒ h = 10° - 1°

⇒ h = 9°

Therefore, the value of h is 9°

What is the value of h? 
h = 1.5°, h = 9°, h = 10°, h = 13.5°

Summary:

The value of h from the given figure is 9°.