Question

You are walking near a river. While standing at A, you measure an angle of 90° between B and C, as shown. You then walk to B and measure an angle of 77° between A and C. The distance between A and B is about 1.5 miles. How wide (in miles) is the river between A and C? Round your answer to the nearest tenth.

Answer 1

Length of AC = 6.67 miles

Explanation:

Given:

Angel between B and C = 90°

Angel between A and C = 77°

AB = 1.5 miles

Find:

Length of AC

Computation:

Using trigonometric laws

Cos 77° = Base / hypotenuses

0.225 = 1.5 / hypotenuses

hypotenuses = 6.67 miles

Length of AC = 6.67 miles