Hello, Ph4m!

Let .As shown in the diagram, a cottage is located at C on an island in the lake,

and a marine is located at B.

If the distance AD = 10.0 km, and <ABC = <CAB = 28°, find distance BC.Code:A * * ** * * * * 28° * * * * * 10.0 km * *x * * * * * 28° 124° * 56° * * * * * * * * * * * * * * B x C D

Since , triangle ABC is isosceles.

Hence: . .

Since , then: .

In right triangle ADC, we have: .

Therefore: . km.