Pinhole camera?

Question

A student has built a 20cm long pinhole camera for a science fair project. she wants to photograph the Washington monument, which is 167cm tall, and to have the image on the film be 5.0 cm high. how far should she stand from the Washington monument?

Thanks for helping~

Answer 1

di over do = hi over ho right?

figure it out! you're not gonna learn with people doing your hwk for you ;)

Answer 2

Make a diagram; there are similar triangles on the object and image sides of the pinhole. (There's probably an identical sample problem if you actually look in your book.)

Answer 3

Do you really think the Washington Monument is 167 cm tall?

Once you get your input right, think similar triangles.