SOLUTION: Pelipa is adding a second story to her house. The addition is rectangular, and the outside dimensions of the walls are 18 feet (east to west) and 28 feet(north to south). The roof

Question 15100: Pelipa is adding a second story to her house. The addition is rectangular, and the outside dimensions of the walls are 18 feet (east to west) and 28 feet(north to south). The roof will have a 4-12 slope with the ridge running north and south. There will be a 9 inch overhang on all sides of the roof. Pelipa needs to order shigles now so that they will be on the job site when she is ready for them. The roofing company waants to know how many squares of shingles she will need.
Deal with this qustion for Pelipa. There may be some terms and concepts in the information given that you will need to research. Make careful drawings and calculatons. Explain how you arive at your estimate
Answer by bam878s(77) (Show Source):
You can put this solution on YOUR website!
I can't draw any pictures on this, but we know that if you're looking at the north side of the house the highest point of the roof will be (1/2)*18 = 9 feet.
Since the slope is 4 in 12 we know the roof rises 4" for every foot of run or 1 foot for every 3 feet of run.
So for 9 feet of run the total rise of the roof is 3 feet.
So to solve for the length of the diagonal side we use the pythagorean theorem.
=
90 =
= diagonal
To figure out how many shingles we need, we need to find total area on the roof. the area of one half the roof is , but we need the area of the full roof + 9 inches of overhang on all sides. Note 9 inches = 3/4 of a foot.
So the area is 2[area of one-half the roof]
2[*
= 588.6178964
Now, 1 square of shingles will cover 100 square feet.
so we need 5 squares for 500 square feet and extra to cover the extra 88.6178964
So to be safe, she should order 6 squares of shingles or 600 square feet.
Hope the lack of pictures doesn't get you mixed up.