Kyle is at the end of a pier 30 feet above the ocean. His eye level is 5 feet above the pier. He is using binoculars to watch a whale surface in the water below.

Question

If the angle of depression to the whale is 20 degrees, how far is the whale from Kyle's binocular?

Round to the nearest 10th.

Answer 1

Draw and label a diagram.

d represents the distance to the whale

tan 20° = 35 / d

Can you solve for d and answer?

Answer 2

a=35

b=?

c=?

α=20

β=70

π=90

You want side c.

a/sinα=b/sinβ=c (sin of a rt angle =1)

35/.342=102.33315........