The measure of an angle is 30° less than its supplement. Find the measure of the angle.

Let the angle be x.

Its supplement is (180° - x).

The problem states the angle is 30° less than its supplement.

∴ x = (180° - x) - 30°

⇒ x = 150° - x

⇒ x + x = 150°

⇒ 2x = 150°

⇒ x = $\dfrac{150^{\circ}}{2}$

⇒ x = 75°

Hence, the required angle measures 75°.