Answer:
The minimum number of rolls to buy is 9
Step-by-step explanation:
step 1
Find the perimeter of the ceiling of Katie’s living room
The perimeter of a square is equal to
[tex]P=4b[/tex]
where
b is the length side of the square
we have
[tex]b=12\ ft[/tex]
so
[tex]P=4(12)=48\ ft[/tex]
step 2
Find the length side of the diagonals of the ceiling
Applying Pythagoras theorem
[tex]d=\sqrt{12^{2} +12^{2}}\\ \\d=\sqrt{288}=16.97\ ft[/tex]
step 3
Find the total crepe paper needed
Sum the perimeter plus two times the length side of the diagonal
[tex]48\ ft+2*(16.97\ ft)=81.94\ ft[/tex]
step 4
Find the number of rolls needed
we know that
Each roll contain 10 ft of crepe paper
so
[tex]81.94/10=8.19\ rolls[/tex]
Round up
[tex]8.19=9\ rolls[/tex]
The minimum number of rolls to buy is 9
