In triangle ABC, angle B = 62 degrees, and angle A is 20 degrees less than angle C.

In triangle ABC, angle B = 62 degrees, and angle A is 20 degrees less than angle C. Find the degree measure of the angle A and determine the shape of the triangle ABC.

1. Let the angle C of the triangle ABC be equal to x degrees.

2. The angle A of this triangle is equal to:

(x – 20) degrees.

3. Draw up an equation and use this equation to determine the value of one of the angles.

x + x – 20 + 62 = 180;

2x = 180 – 42 = 138;

x = 138/2 = 69 °.

Answer: C = x = 69 °, A = x – 20 = 69 – 20 = 49 °, B = 62 °. The ABC triangle is acute-angled, since all corners are sharp.