If angle B measures 25°, what is the approximate perimeter of the triangle below? A right triangle is shown. Angle A is 90 degrees and angle B is 25 degrees. Side AB has a length of 4.

Solution:

Given,

From the ΔABC

∠A = 90°, ∠B = 25°

∠C = 180° - 90° - 25° = 65°.

AB = c = 4 units.

From the sine rule,

A/sin A = B/sin B = C/sin C

BC/sin 90 = AC/sin 25 = 4/sin 65 

AC = 4 (sin 25/sin 65)

AC = 1.86 unit.

BC = 4(sin 90/sin60) 

BC = 4.62 unit

Perimeter of the triangle = AB + BC + CA

Perimeter of the triangle = 4 + 4.62 + 1.86

Perimeter of the triangle = 10.48 units.

Therefore, the approximate perimeter of the triangle is 10.48 units.

If angle B measures 25°, what is the approximate perimeter of the triangle below? A right triangle is shown. Angle A is 90 degrees and angle B is 25 degrees. Side AB has a length of 4.

Summary:

If angle B measures 25°, the approximate perimeter of the triangle is 10.48 units. A right triangle is shown. Angle A is 90 degrees and angle B is 25 degrees. Side AB has a length of 4.