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What is the name of the shape that is 3D and irregular? |
2007-06-14 |
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From alan:
What is the name of the shape that is 3D and irregular?
Answered by Stephen La Rocque and Penny Nom. |
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Circumscribing a golden cuboid with a sphere: surface areas |
2007-06-14 |
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From Ainslie:
A golden cuboid is defined as a rectangular prism whose length, width and height are in the ratio of phi : 1 : 1/phi.
Prove that the ratio of the Surface Areas of the golden cuboid to that of the sphere that circumscribes it is Phi : Pi.
Answered by Stephen La Rocque. |
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A geometry problem |
2007-06-14 |
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From Shamik:
ABC is any triangle and D and E are 2 points on AB and AC, respectively. M
is the mid-point of BE and N is the mid-point of CD. Prove that the area of
the triangle (AMN) is 1/4 of that of the quadrilateral(BCED).
Use plane-geometry without using co-ordinates to find the solution.
Answered by Shamik Banerjee and Chris Fisher. |
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A system of linear equations |
2007-06-14 |
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From Alfredo:
A student club sponsored a jazz concert and charged $3 admission for students, $5 for faculty, and $8 for the general public. The total ticket sales amounted to $2542.
Three times as many students bought tickets as faculty. The general public bought twice as many tickets as did the students. Set up the equations that determine how many
tickets were sold to each group and solve.
Answered by Stephen La Rocque and Penny Nom. |
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The composition of functions |
2007-06-14 |
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From Gilligan:
Question from Gilligan, a student:
Let f(x) = x^2, g(x) = 3x and h(x) = (sqrt{x}) + 1. Express each function as a composite of f, g and/or h.
(1) p(x) = 3(sqrt{x}) + 3
(2) Q(x) = (sqrt(sqrt{x}) + 1}) + 1
Answered by Penny Nom. |
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Angles of depression |
2007-06-13 |
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From Phonda:
The pilot of a small private plane can look forward and see the control tower for a small airstrip. Beyond that is a large factory that is 3 milies from the airstrip. The angles of depression are 12.5 degrees and 4.8 degrees respectively.
Find the airplane's altitude, to the nearest ten feet.
Answered by Stephen La Rocque. |
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A probability problem |
2007-06-13 |
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From Lina:
A point P is selected at random from the interior of the pentagon with vertices
A = (0,2), B = (4,0), C = (2 π+1,0), D = (2 π+1,4), and E = (0,4). What is the probability
that
Answered by Stephen La Rocque and Penny Nom. |
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Looking in the mirror |
2007-06-13 |
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From annafe:
why do you think that when you look at the mirror your face is just the same as what it is,while when you read messages on the mirror,it is in inverse?
Answered by Stephen La Rocque. |
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The size of a lot |
2007-06-13 |
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From Larry:
This is driving me crazy, I know i learned this in college but that was so many years ago haha. I am trying to determine how many acres
my property is. Unfortunately everywhere i look is like another language to me when seeing these formulas. My property is square shaped
so starting from one side and just working around the dimensions are: 114 feet x 95.88 feet x 100 feet x 91.91 feet.
Answered by Penny Nom. |
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What is the size of the circle it would make? |
2007-06-13 |
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From ed:
i have a piece of sheet metal 56' 6" long what is the size of the circle it would make
Answered by Penny Nom. |
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Standard Deviation |
2007-06-13 |
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From Adrian:
If you are told that the mean salary of a certain group of workers is $30,000 with a standard deviation of $4000, what proportion of workers earn over $38,000? What proportion of workers earn less than $18,000? Assume the distribution of wages is normal.
Answered by Stephen La Rocque. |
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Percentage increase and decrease |
2007-06-13 |
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From Anna:
I just want to if the following formula is used for the computation of a PERCENTAGE DECREASE:
Old Value - New Value/ Old Value x 100%
My immediate superior is under the impression that the said formula works ONLY for the computation of a percentage INCREASE. He believes that the formula for a percentage DECREASE:
Old Value - New Value/ NEW Value x 100%
On this score, I want to know the correct formula for the computation of percentage decrease. Thank you so much.
Answered by Penny Nom. |
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Express a certain variable as a function of another variable |
2007-06-12 |
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From Gilligan:
The volume V of a right circular cone is V = (1/3)pi(r^2)(h). If the height is TWICE the radius, express the volume V as a function of r.
I see the phrase "express a certain variable as a function of another variable" a lot in math books.
What exactly does that mean?
Is there another way to say the same thing?
Answered by Stephen La Rocque. |
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Composition functions |
2007-06-12 |
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From Gilligan:
Find functions f and g so that f(g(x)) = H.
(1) H(x) = (1 + x^2)^(3/2)
(2) H(x) = int(x^2 + 1)
I don't know where to start.
Answered by Stephen La Rocque. |
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A ten- foot long board is cut into three pieces |
2007-06-12 |
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From Cynthia:
How do I solve this problem?
A ten- foot long board is cut into three pieces. The second piece is half
as long as the first. The third piece is 4 1/2 longer than the second.
How long is the first?
Answered by Penny Nom. |
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