Is this proportional
1 answer:
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Answer:
the total number of shingles is 3060
Step-by-step explanation:
Please have a look at the attached photo.
We need to find the total are of the roof.
The are of the trapezoid is:
- A = 1/2 (base 1 + base 2) height
= 1/2 (20+30)*15
= 375
The are of the triangle:
- A = 1/2*base*height
= 1/2(1.5*10)
= 7.5
=> We need to find the total are of the roof is:
The are of the 2 trapezoids + The are of the 2 triangles
= 375 *2 + 7.5
*2
= 765
Given in the question that, the shingles are 1 foot by 1 foot, but they overlap by 0.75 square foot so the usable area of the shingle is only 0.25
So the total number of shingles is:
765 / 0.25
= 3060
