Question

PLEASE HELP!!!!

A 7ft. tall basketball player is walking towards a 17ft tall lamppost at a rate of 4 ft/sec. Assume the scenario can he modeled with right triangles. Find the rate the length of the player’s shadow is changing when he is 12 feet from the lamppost.

Answer 1

Answer: In simple terms

Explanation:

At 12ft from the lamppost:

Let's call the length of the shadow S.

We can see part of a right triangle formed by the player's height (7ft), the distance to the lamppost (12ft), and the hypotenuse which is the length of the shadow (S ft).

Using the Pythagorean theorem:

72 + 122 = S2

49 + 144 = 193

Therefore, at 12ft from the lamppost:

The length of the shadow (S) = 13ft

To find the rate at the shadow is changing:

As the player walks closer at 4ft/sec, the distance to the lamppost decreases by 4ft each second.

For each 4ft closer, the shadow length changes by:

Shadow length (13ft) x (4ft/12ft distance) = 2ft

So the shadow length changes by 2ft for each 4ft the player walks closer.

Therefore, the rate at the shadow length is changing at 12ft from the lamppost is:

2ft / 4ft walked closer = 0.5 ft/sec