SOLUTION: Benjamin made a model of a square pyramid with a square base5 inches long and a slant height of nine inches as shown. The surface area of the pyramid is given by the formula SA=

Algebra ->  Customizable Word Problem Solvers  -> Geometry -> SOLUTION: Benjamin made a model of a square pyramid with a square base5 inches long and a slant height of nine inches as shown. The surface area of the pyramid is given by the formula SA=      Log On

Ad: Over 600 Algebra Word Problems at edhelper.com


   



Question 954361: Benjamin made a model of a square pyramid with a square base5 inches long and a slant height of nine inches as shown.
The surface area of the pyramid is given by the formula SA= B+1/2 p
What is the surface of Benjamin's pyramid?

Answer by macston(5194) About Me  (Show Source):
You can put this solution on YOUR website!
B=area of base; P=perimeter of base=20 in; s=slant height=9 inches; b=edge of base=5 inches
The formula for surface area is:
S.A.=B%2B%281%2F2%29Ps
The %281%2F2%29Ps is derived from the formula for the area of a triangle:
A=%281%2F2%29bs where b is edge of the base is the area of one side.
4%281%2F2%29bs=2bs would be all four sides. P=4b so 1/2P=2b and we wind up with
%281%2F2%29Ps instead of 2bs.
But the s is missing from the given formula:If you use the given formula, you will not get the true correct answer, but if you use the correct formula, you will not get an answer for the given formula. It's your choice. Check the original problem to see if you overlooked the s when posting.
SA=B%2B%281%2F2%29Ps
SA=%285%5E2in%5E2%29%2B%281%2F2%29%2820in%29%289in%29=25in%5E2%2B90in%5E2=115in%5E2%29
ANSWER: The surface area is 115 square inches.