The angles of triangle are in A.P. whose common difference is 20°. Find angles.

Let the three angles of triangle in A.P. be represented as : a - d, a, a + d.

The sum of the interior angles of any triangle is always 180°.

⇒ a - d + a + a + d = 180°

⇒ 3a = 180

⇒ a = $\dfrac{180}{3}$

⇒ a = 60°.

Given,

The common difference is 20°

⇒ a - 20° = 60° - 20° = 40°

⇒ a + 20° = 60° + 20° = 80°.

Hence, the angles of triangle are 40°, 60°, 80°.