Question

In ΔABC, BC = AC and ∠B = 65°.

∴ ∠C = ______.

Options

• 65°

• 50°

• 115°

• 55°

Answer 1

∴ ∠C = 50°.

Explanation:

Since BC = AC, triangle ABC is isosceles.

In an isosceles triangle, the base angles are congruent.

Therefore, ∠B = ∠C.

Given that ∠B = 65°, we can use the angle sum property of a triangle:

Angle sum of triangle = 180°

∠A + ∠B + ∠C = 180°

Since ∠B = ∠C,

∠A + 65° + 65° = 180°

∠A + 130° = 180°

∠A = 50°

Thus, ∠C = 50°.