from a lighthouse 75.3 feet above the level of the water, the angle of depression of a boat is 23 degrees 40'. how far is the boat from a point of water level directly under the point of observation?
40' = [40/60] ° = [2/3] °
We can use the tangent function, here
tan [ 23 + 2/3] = 75.3 / D where D is the distance we want........solve for D
D = 75.3 / tan [23 + 2/3 ] = about 171.8 ft
+185 
