Answer:
5.13 feet
Explanation:
Engine is driving the propeller with a radius of 8 feet and its centerline 13 feet above the ground.
And the speed is 700 revolutions per minute, the height of one propeller tip as a function of time is given by:

We have been asked to find the value of height, 'h', when t=4 minutes.
Plugging the value of time, 't', in the equation, we already know that we need to use degrees (not radians) we get:






So the height of one propeller tip at t=4 minutes is 5.13 feet.