Question

To find the height of a fir tree, Bill first found the length of the tree's shadow to be 80 feet long. At the same time, he held a yardstick perpendicular to the ground. The yardstick cast a shadow of 4 feet. What was the height of the tree?

(Hint: How many feet are in a yardstick)

Answer 1

Answer: 60 ft

Explanation:

We can set up ratios to solve this problem. First, let's use x to represent the actual height of the tree. The tree, with heigh x, casts a shadow of 80 feet.

This gives us a ratio of 80:x

Next, they say that a yardstick (1 yd = 3 ft) casts a shadow of 4 ft. Therefore we can set up a ratio of 4:3.

We can compare these ratios by saying

80/x = 4/3. By cross multiplying, you get that 4x = 240.

x = 60 ft