Find the unknown number using cross multiplication 20/0.64 = 130/X

To find the unknown number using cross multiplication, we can set up the equation as follows:

20/0.64 = 130/X

First, we can cross multiply by multiplying the numerator of the first fraction (20) by the denominator of the second fraction (X).

20 * X = 0.64 * 130

Next, we can simplify the equation by multiplying the numbers on the right side of the equation.

20X = 83.2

To isolate X, we divide both sides of the equation by 20.

X = 83.2/20

Evaluating the division gives us:

X = 4.16

Therefore, the unknown number is 4.16.