Q. 54.9( 24 Votes )
In the adjacent triangle ABC, find the value of x and calculate the measure of all the angles of the triangle.

Answer :
Given:
∠A = x + 15, ∠B = x - 15, ∠ C = x + 30
As we know, using theorem (1), in any triangle, sum of the three interior angles is 180°.
So,
∠A + ∠B + ∠ C = 180°
⇒ x +15 + x – 15 + x + 30 = 180°
⇒ 3x + 30° = 180°
⇒ 3x = 180° - 30°
⇒ 3x = 150°
⇒ x = 50°
So, the angles are,
∠A = x + 15 = 50° + 15° = 65°
∠B = x - 15 = 50° - 15° = 35°
∠ C = x + 30 = 50° + 30° = 80°
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