Hey there!
3/36 = x/72
FIRST: CROSS MULTIPLY the equation
3 * 72 = x * 36
3 * 72 = 36 * x
216 = 36x
36x = 216
SECOND: DIVIDE 36 to BOTH SIDES
36x/36 = 216/36
CANCEL out: 36/36 because it give you 1
KEEP: 216/36 because it help solve for the x-value
NEW EQUATION: x = 216/36
THIRD: SIMPLIFY IT!
x = 6
Therefore, your answer is: x = 6
Good luck on your assignment & enjoy your day!
~Amphitrite1040:)