Question

Two similar figures have a side ratio of 4:3. If the perimeter of the smaller figure is 15 units, what is the perimeter of the larger figure?

Answer 1

Answer:

20 units

Step-by-step explanation:

The 3 part of the ratio  refers to 15 units

Divide 15 by 3 to find the value of one part of the ratio

15 ÷ 3 = 5 ← value of 1 part of the ratio, thus

4 parts = 4 × 5 = 20 units ← perimeter of larger figure

Answer 2

Answer: The answer is 20 units

Step-by-step explanation: The question stipulates that two figures have their sides in the ratio of 4:3.

This implies that for every side in the smaller figure, the corresponding side in the larger figure measures times 4/3 (that is, divided by 3 and then multiplied by 4)

Therefore if for example, one side in the smaller figure measures 9 units, then the corresponding side in the larger figure would measure

9 * 4/3.

However, if the corresponding side is represented by x for example, then

9/x = 3/4. (This makes the ratio of the left hand side equal to that on the right hand side)

By cross multiplication you now have

9(4) = 3x

36 = 3x

Divide both sides of the equation by 3, and you have

x equals 12.

Hence, if the perimeter of the smaller figure is 15 units, the perimeter of the larger figure would be calculated as

Perimeter of larger figure

15/x = 3/4

By cross multiplication you now have

15(4) = 3x

60 = 3x

Divide both sides of the equation by 3

20 = x

Therefore the perimeter of the larger figure is 20 units