We need to calculate the surface area
We have 6 faces and three different rectangles
The red rectangles are equals
The green rectangles are equals
The blue rectangles are equals
The formula for the area of a rectangle is
[tex]A=l\times w[/tex]
where
l is the length
w is the width
The area for one red rectangle
l=10
w=5
[tex]A_R=10\times5=50[/tex]
The area for one green rectangle is
l=10
w=7
[tex]A_G=10\times7=70[/tex]
The area for one blue rectangle
l=7
w=5
[tex]A_B=7\times5=35[/tex]
The total area is
[tex]A=2A_R+2A_G+2A_B=2(50)+2(70)+2(35)=100+140+70=310in^2[/tex]
Then we need to transform the square inches to square feet
1 square ft = 144 square inches
x square ft = 310 square inches
[tex]x=\frac{310}{144}=2.15\text{ }[/tex]
Mrs Harris will need 2.15 square ft to wrap the prism
