Arithmetic Grade Five
Lesson One hundred and Sixty: Perimeter
Jill wants to measure her yard. She has a stick which she knows is five
feet in length. She finds that her yard (which is rectangular) is 20 stick
lengths long and 15 stick lenghts wide. What is the perimeter of Jill's yard
in feet?
stick lengths feet
length 20 100
width 15 75
In stick lengths, Jill's yard measures 20 by 15. In feet, therefore,
her yard measures 100 by 75. Once we know the length and width of the
yard in feet we can find the perimeter in the usual way:
(100 + 75) * 2 = 350 feet
Jill has a basketball court in her backyard (which, as you would expect,
is rectangular). She has a pole which is 8 feet long which she decides to
use as her measuring device. She finds that the basketball court is three
pole lengths wide and five pole lengths long. What is the perimeter of her
basketball court in feet?
pole lengths feet
length 5 40
width 3 24
Perimeter: (40 + 24) * 2 = 128 feet