Proportions as equations: 3 is to 7 as 6 is to x, 5 is to 7 as x is to 21, 7 is to 35 as 5 is to x
You're dealing with fractions. The first item mentions becomes the numerator, and the second item
becomes the denominator. The word "as" becomes the equal sign. Then the third item becomes
the numerator for the second fraction, and the final item becomes the denominator for the second fraction.
3/7 = 6/x
5/7 = x/21
7/35 = 5/x
You solve each equation for its x value.
3/7 = 6/x 3/7 x = 6 3x = 7*6 = 42 x = 42/3 = 14 3/7 = 6/14 The right side reduces to 3/7
5/7 = x/21 21 * (5/7) = x 105/7 = x x = 15 5/7 = 15/21 The right side reduces to 5/7
7/35 = 5/x 7/35 x = 5 7x = 5*35 = 175 x = 175/7 = 25 7/35 = 5/25 Both sides reduce to 1/5