Which number makes the following number sentence true 3+6=6+

3

Step-by-step explanation:

3 + 6 = 6 + 3

Step-by-step explanation:

3 + 6 = 6 + y

9 = 6 + y

y + 6 = 9

y + 6 - 6 = 9 - 6

y = 3

56.6

step-by-step explanation:

the ratio of the perimeters is equal to the scale.

the ratio of the areas is equal to the square of the scale.

34 / 20 = k

a / 19.6 = k²

substituting:

a / 19.6 = (34 / 20)²

a = 19.6 (34 / 20)²

a ≈ 56.6