Question

A proportion is shown below.

7/10 = 17.5/x

What is the value of x?

Answer 1

Ahh -- ratios and proportions are soooo useful!

7/10 = 17.5/x


Cross multiply.

7x = 10 * 17.5

Solve for x.

7x = 175

x = 175/7

x = 25

Answer 2

this is how I solve, seems totally wrong.

(17.5*7)/10 = x

122.5/10 = x

12.25 = x

x = 12.25

Answer 3

First, you could see it's wrong. Since 7 is less than 10, then 17.5 must be less than x.

Study this site, especially Method 1 under Solutions.

http://www.regentsprep.org/Regents/math/ALGEBRA/AO3/Lprop.htm

Answer 4

thank you Ms.Sue :)

Answer 5

Oh i see, thank you for the link, that helps a lot.

Answer 6

You're welcome.