Question

How to show the ratio 3:8 is equal to 12:32

Answer 1

$3:8=\dfrac{3}{8}=\dfrac{3\cdot4}{8\cdot4}=\dfrac{12}{32}=12:32\\\\3:8=12:32$

Answer 2

12:32 is simply 3:8 but divided by 4 to both sides.