How many millimeters are in 8 inches?

Question

Here is a picture:

8in/?mm = 40in/1,016

A. 127mm

B. 163.2mm

C. 167mm

D. 203.2mm

Answer 1

Using your ratios:

8in=?mm

40in=1016mm so ratio is 1in=1016/40=25.4mm

So 8in=8*1 in=8*25.4mm=203.2mm, answer D.

Another way to do it: if 40in=1016mm, then divide by 5: 8in=1016/5=203.2mm, answer D.

Using my ratios:

2.54cm=1in. 8in=8*2.54cm=20.32cm.

1cm=10mm, so 20.32cm=10*20.32mm=203.2mm, answer D.

See, the answers are all the same! That means there is often more than one way to solve the same problem.

Comments

I hope you saw my extended answer. It shows how you can work out the answer from ratios in different ways.