Question

Use cross products to identify the equation needed to solve this proportion:

5
x
=
2
9

Answer 1

x=22.5

Explanation:

We are given the proportion:

5/x=2/9

Cross multiply. Multiply the numerator (top number) of the first fraction by the denominator (bottom number) of the second. Then multiply the denominator of the first by the numerator of the second.

5*9=2*x

45=2x

2 and x are being multiplied. The opposite of multiplication is division. Divide both sides by 2. This will cancel out the 2 being multiplied by x, and leave x by itself.

45/2=2x/2

45/2=x

22.5=x

If we substitute 22.5 in for x, the final proportion will be:

5/22.5=2/9