A rectangle has a perimeter of 30 cm. What would be the new perimeter if the length and width of the rectangle is doubled in size?
The new perimeter would be 60.
Let's say the length is 10 and the width is 5.
2 10 = 20 and 2 5 = 10
20 + 10 = 30 <== The old perimeter
If we double 10 and 5 we get 20 and 10 as the new length and width.
2 20 = 40 and 2 10 = 20
40 + 20 = 60 <== The new perimeter
Perimeter of the rectangle:
2 L + 2 W = 30 cm
2 ( L + W ) = 30 cm
If the length and width of the rectangle is doubled in size the new perimeter would be:
2 ( 2 L + 2 W ) = 2 · 2 ( L + W ) = 2 · 30 cm = 60 cm