Originally Posted by

**mmonkman** Hi, I received this question today. I need help with the placement of the 120 degree angle and 20 degree angle. The wording is confusing. Any help is appreciated.

Thanks!

A surveyor is measuring the length of a lake. He takes angle

measurements from two positions, A and B, that are 136 m apart

and on the same side of the lake. From B, the measure of the angle

between the sight lines to the ends of the lake is 130°, and the

measure of the angle between the sight lines to A and one end of

the lake is 120°. From A, the measure of the angle between the

sight lines to the ends of the lake is 65°, and the measure of the

angle between the sight lines to B and the same end of the lake is

20°. Calculate the length of the lake, to the nearest metre.