Answer:
The minimum number of rolls she should buy is 9 rolls
Step-by-step explanation:
* Lets study the information in the problem
- Katie wants to put the crepe paper around the perimeter of the
ceiling which shaped a square of side length 12 feet
- And also from each corner to the opposite corner
- She needs the length of the 4 sides of the square and the length
of its 2 diagonals
* Lets find the length of the diagonal of the square
∵ The two adjacent sides of the square formed two legs of a right
angle triangle and the diagonal joining the endpoints of the legs
is the hypotenuse of the triangle
- Use Pythagoras theorem to find the length of the diagonal
∴ The length of the diagonal = √(s² + s²) √(2s²) = s√2
∵ The length of the side of the square = 12 feet
∴ The length of the diagonal = 12√2
* Now lets find the length of the crepe papers she needs
∵ She needs the length of the 4 sides of the square and the length
of its 2 diagonals
∴ The length of crepe papers = 12 + 12 + 12 + 12 + 12√2 + 12√2 = 81.94 feet
∵ Each roll of the crepe papers contain 10 feet
- To find the number of rolls divide the length of the crepe papers by 10
∴ The number of rolls = 81.94 ÷ 10 = 8.194
* She must to buy 9 rolls to have enough crepe papers to decorate
her ceiling
* V.I.N:
- If she decide to buy 8 rolls, some part of ceiling will not decorate
because the 8 rolls have 80 feet only and she needs 81.94 feet
