surface area (S) of a right rectangular solid is:
S = 2*L*W + 2*L*H + 2*W*H (equation 1)
where:
L = length
W = width
H = height
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you have:
L = 7
W = a
H = 4
-----
formula becomes:
S = 2*7*a + 2*7*4 + 2*a*4
simplify:
S = 14*a + 56 + 8*a
combine like terms:
S = 22*a + 56
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answer is:
S = 22*a + 56 (equation 2)
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to prove, substitute any value for a in equation 2:
let a = 15
S = 22*a + 56 (equation 2)
S = 22*15 + 56
S = 330 + 56
S = 386
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since a = 15, then W = 15 because W = a
go back to equation 1 and substitute 15 for W:
S = 2*L*W + 2*L*H + 2*W*H (equation 1)
where:
L = length
W = width
H = height
-----
you have:
L = 7
W = 15
H = 4
-----
equation 1 becomes:
S = 2*7*15 + 2*7*4 + 2*15*4
perform indicated operations:
S = 210 + 56 + 120
S = 386
-----
surface area is the same using both equations so:
equations are good.
formula for surface area of right rectangle in terms of a is:
S = 22*a + 56
-----
now, let's recall Cavalieri's Principle, "solids with equal altitudes and cross-sectional areas at each height, have the same volume".
so, even though this cylinder is slanted, it has the same cross-sectional area as a cylinder that's straight-up, whose altitude is h = 5, and radius r = 4.
Answer:
1) Yes it has a 90° angle at point B.
2) No it has no points of 90° angles. Even though point y looks like it, the line from y to x is not straight like an L from line y to z.
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Answer:
q = -13
Step-by-step explanation:
The given equation is:
Taking 2 as common from left hand side, we get:
![2(x^{2}-4x)=5\\\\2[x^{2} - 2(x)(2)]=5](https://tex.z-dn.net/?f=2%28x%5E%7B2%7D-4x%29%3D5%5C%5C%5C%5C2%5Bx%5E%7B2%7D%20-%202%28x%29%282%29%5D%3D5)
The square of difference is written as:
Equation 1
If we compare the given equation from previous step to formula in Equation 1, we note that we have square of first term(x), twice the product of 1st term(x) and second term(2) and the square of second term(2) is missing. So in order to complete the square we need to add and subtract square of 2 to right hand side. i.e.
![2[x^{2}-2(x)(2)+(2)^2-(2)^{2}]=5\\\\ 2[x^{2}-2(x)(2)+(2)^2]-2(2)^{2}=5\\\\ 2(x-2)^{2}-2(4)=5\\\\ 2(x-2)^2-8=5\\\\ 2(x-2)^{2}-8-5=0\\\\ 2(x-2)^{2}-13=0](https://tex.z-dn.net/?f=2%5Bx%5E%7B2%7D-2%28x%29%282%29%2B%282%29%5E2-%282%29%5E%7B2%7D%5D%3D5%5C%5C%5C%5C%202%5Bx%5E%7B2%7D-2%28x%29%282%29%2B%282%29%5E2%5D-2%282%29%5E%7B2%7D%3D5%5C%5C%5C%5C%202%28x-2%29%5E%7B2%7D-2%284%29%3D5%5C%5C%5C%5C%202%28x-2%29%5E2-8%3D5%5C%5C%5C%5C%202%28x-2%29%5E%7B2%7D-8-5%3D0%5C%5C%5C%5C%202%28x-2%29%5E%7B2%7D-13%3D0)
Comparing the above equation with the given equation:
, we can say:
p = 2 and q= -13
