Question

A boat is on the same horizontal level as the foot of a cliff and the angle of depression of the boat 30 degree. If the boat is 120m away from the foot of the Cliff, find the height of the Cliff to 3 significant figures​

Answer 1

69.282 m

Explanation:

We can use the trigonometry of right triangles to solve this, since we are in the presence of a right triangle with acute angle 30 degrees, opposite side unknown (the vertical height of the cliff), and adjacent side equal to 120 m.

we use the tangent function to solve for the unknown, as shown below:

tan(30) = x/120

x = 120 * tan(30) = 69.282 m