A triangular pennant has two sides that are 90 cm long each with an included angle of 25°.

What is the area of this pennant?

Enter your answer as a decimal in the box. Round only your final answer to the nearest tenth.

We are given with the following value:

AB = BC = 90 cm

∠B = 25°

∠D=90°

Solving the ∠C:

180 ° = (∠B/2) + ∠D + ∠C

180° = (25°/2) + 90° + ∠C

180° - 12.5° - 90° = ∠C

∠C = 77.5°

Solving for length in mD:

sin 77.5° = mD/90

mD = 90 sin77.5°

mD = 87.87

Solving for mDC:

cos 77.5 = mDC/90

mDC = 90 cos 77.5°

mDC = 19.48

Area = 1/2 * Base * Height

Area = 1/2 * 19.48*87.87

Area = 855.834

The total area of triangular pennant = 2 x 855.834 = 1,711.67 cm².

The area is 1,711.67 cm².