Question

Thomas decides to use the method of proportions and similar

triangles to find the height of a lamppost. He measures the length of
the post's shadow and finds it is 5 feet long. Then, he holds a 1-foot
ruler perpendicular to the ground and finds that it casts a 2-inch
shadow. How tall is the lamppost?
a. 2.5 ft c. 30 ft
b. 12 ft d. 60 ft

Answer 1

I’m pretty sure it’s C

Answer 2

The lamppost is 30 ft tall.

Explanation:

You need to draw a diagram of the problem. Refer to attachment.

Now you need to convert the measurements that are in feet to in. The 1 foot ruler is now 12 in. and the 5 foot post's shadow is now 60 in.

The next step is to create a proportion between both angles.
`(x)/(1) =(60)/(2)`

x over 1 is simplified to x and 60 divided by 2 is just 30. So the lamppost is 30 ft tall.

Hope that helped. :)