Question

When the shadow of a flagpole is 36 m long, a 1.8-m fencepost casts a shadow that is 3 m long. How tall is the flagpole?

Answer 1

21.6 m long

Explanation:

To do this, we find the scale factor of the fencepost and the shadow.

3/1.8 = 1.66666667

So, we know that when we take the original length and multiply it, we get the new one, so:

1.666666667 * x = 36

x being the original length. Now, we divide both sides by 1.66666667 to get x alone and find the original length.

x = 21.6

To double check, we can take the scale factor and multiply it by the original to get the shadow.

21.6 * 1.666666667 = 36

It is correct