Question

a water main is to be constructed with a 10% grade in the north direction and a 20% grade in the east direction. determine the angle theta required in the water main for the turn from north to east

Answer 1

26.6degrees

Explanation:

Given

percent grade through north = 10% (opposite)

percent grade through east = 20% (adjacent)

Get the direction

Using the SOH CAH TOA identity

tan theta = opp/adj

tan theta = 10/20

tan theta = 0.5

theta = arctan (0.5)

theta = 26.6degrees

Hence the required angle is 26.6degrees