find missing denominator of 3\7=15\? to show equivalent fraction

Answer 1

3 / 7 = 15 / x Multiply both sides by x

3 x / 7 = 15 Multiply both sides by 7

3 x = 15 * 7

3 x = 105 Divide both sides by 3

x = 105 / 3

x = 35

3 / 7 = 15 / 35

Answer 2

or, since 15 = 3*5, multiply by 5/5 and you have

3/7 = 15/x
15/35 = 15/x
x = 35