Don L. answered • 12/18/15

Fifteen years teaching and tutoring basic math skills and algebra

Hi AmH, let A be a point on one side of the lake. Let O be a point on the opposite side of the lake. One process we can use is to place a third point, call it B, on the same side of the lake as point A.

Measure the distance from point A to point B.

Measure the angles ∠BAO and ∠ABO.

Now knowing two angles, we can find the size of the third angle ∠AOB (remember, the angles in a triangle equal 180 degrees.)

Then we can use the trig relationship of angle, side, angle to find the distance from point A to point O using the law of Sines.

Questions?