You want to cover your sofa cushions with new fabric. Each of your rectangular sofa cushions is 10 cm by 25 cm by 15 cm. You have four sofa cushions that you want to cover with new fabric. How much fabric will you need to use in order to cover these four sofa cushions with new fabric?
Question 2 options:
1)
6,200 cm2
2)
3,100 cm2
3)
1550 cm2
4)
775 cm2
show work
To find the total amount of fabric needed, we need to find the total surface area of all four cushions.
The formula for surface area of a rectangular prism (which a cushion can be thought of as) is:
2lw + 2lh + 2wh
So for each cushion:
2(10 cm x 25 cm) + 2(10 cm x 15 cm) + 2(25 cm x 15 cm)
= 500 + 300 + 750
= 1550 cm2
And for all four cushions:
4 x 1550 cm2 = 6200 cm2
Therefore, the answer is option 1) 6,200 cm2.