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:

The minimum number of rolls to buy is 9

Explanation:

step 1

Find the perimeter of the ceiling of Katie’s living room

The perimeter of a square is equal to

where

b is the length side of the square

we have

so

step 2

Find the length side of the diagonals  of the ceiling

Applying Pythagoras theorem

step 3

Find the total crepe paper needed

Sum the perimeter plus two times the length side of the diagonal

step 4

Find the number of rolls needed

we know that

Each roll contain 10 ft of crepe paper

so

Round up

The minimum number of rolls to buy is 9