Question

The ceiling of Katie’s living room is a square that is 15 ft long on each side. To decorate for a party, she plans to hang crepe paper around the perimeter of the ceiling and then from each corner to the opposite corner. Katie can buy rolls that each contain 20 ft of crepe paper. What is the minimum number of rolls she should buy? Show your work.

Answer 1

Answer:

6 rolls because the total perimeter is 102 ft and five rolls is only 100 feet. So she needs 6 rolls.

Step-by-step explanation:

to find perimeter, add up all the side lengths.

so 15*4 (it's easier than 15+15+15...)

60 ft.

now we have to use Pythagorean's Theorum to find corner to corner.

so $a^2+b^2=c^2$

we have a and b

$15^2+15^2=c^2$

do the math...

225+225= 450

square root of 450=

21.213

double that because it's used twice (corner to corner and corner to corner)

42.426

now add it all up

42.426 + 60 = 102.426

we can round

102

20*5 = 100

so she needs 6

MY ORIGINAL ERROR WAS 5, BUT 5 TIMES 20 IS ONLY 80, SO THEREFORE 6 IS REQUIRED SO THERE IS ENOUGH TO COVER 102.