A. The volume of a pyramid is given by the formula V = (1/3)Bh, where B is the area of the base and h is the height. In this case, the base is a square with side length 10cm, so B = 10^2 = 100cm^2. The height of the pyramid is 15cm. Therefore, the volume of the pyramid is V = (1/3)(100cm^2)(15cm) = 500cm^3.
B. A frustum is the part of a pyramid that remains after the top portion has been removed by a plane parallel to the base. The volume of a frustum is given by the formula V = (1/3)h (B1 + B2 + (B1B2)^0.5), where B1 and B2 are the areas of the top and bottom bases, h is the height of the frustum, and (B1B2)^0.5 is the geometric mean of the areas of the two bases.
In this case, the top 6cm of the pyramid have been removed, so the height of the frustum is 15cm - 6cm = 9cm. The area of the new top base is 6/10 of the area of the original base, since it has been reduced by a factor of 6/10 along each side. Therefore, B2 = (6/10)^2(100cm^2) = 36cm^2.
Using the same logic, the geometric mean of the areas of the two bases is (36cm^2)(100cm^2)^0.5 = 600cm^2.
Thus, the volume of the frustum is V = (1/3)(9cm)(100cm^2 + 36cm^2 + 600cm^2) = 5480cm^3.
A right pyramid on a base 10cm square is 15cm high
A. Find the volume of the pyra mid
B. If the top 6m of the pyramid are removed, what is the volume of the remaining frustum.
3 answers
AAAaannndd the bot gets it wrong yet again!
How can you get a volume for the frustrum which is 10 times as big as the original entire pyramid?
the top 6cm is 2/5 the height, so its volume will be 8/125 the original volume, or 8/125 (500) = 32 cm^3
That leaves 468 cm^3 for the frustrum
How can you get a volume for the frustrum which is 10 times as big as the original entire pyramid?
the top 6cm is 2/5 the height, so its volume will be 8/125 the original volume, or 8/125 (500) = 32 cm^3
That leaves 468 cm^3 for the frustrum
I apologize for the mistake in my previous response. You are correct that the volume of the frustum would be significantly smaller than 5480cm^3. The correct method to calculate the volume of the frustum is as follows:
The volume of the original pyramid is 500cm^3, as calculated in part A.
The height of the remaining frustum is (15cm-6cm) = 9cm. The top and bottom faces of the frustum are similar to the original square base, and their areas are in the ratio of (6/10)^2 to 1.
Therefore, the area of the top face is (6/10)^2 x 100cm^2 = 36cm^2, and the area of the bottom face is 100cm^2.
The volume of the frustum can be calculated using the formula for the volume of a frustum:
V = (1/3)h (A1 + A2 + (A1A2)^0.5)
where h is the height of the frustum, A1 and A2 are the areas of the top and bottom faces, and (A1A2)^0.5 is the geometric mean of the two face areas.
Plugging in the values, we get:
V = (1/3) x 9cm x (36cm^2 + 100cm^2 + (36cm^2 x 100cm^2)^0.5)
V = 13.5cm x (136cm^2)^0.5
V = 13.5cm x 11.66cm
V = 157.41cm^3 (rounded to two decimal places)
Therefore, the volume of the remaining frustum is approximately 157.41cm^3. Thank you for bringing the error to my attention.
The volume of the original pyramid is 500cm^3, as calculated in part A.
The height of the remaining frustum is (15cm-6cm) = 9cm. The top and bottom faces of the frustum are similar to the original square base, and their areas are in the ratio of (6/10)^2 to 1.
Therefore, the area of the top face is (6/10)^2 x 100cm^2 = 36cm^2, and the area of the bottom face is 100cm^2.
The volume of the frustum can be calculated using the formula for the volume of a frustum:
V = (1/3)h (A1 + A2 + (A1A2)^0.5)
where h is the height of the frustum, A1 and A2 are the areas of the top and bottom faces, and (A1A2)^0.5 is the geometric mean of the two face areas.
Plugging in the values, we get:
V = (1/3) x 9cm x (36cm^2 + 100cm^2 + (36cm^2 x 100cm^2)^0.5)
V = 13.5cm x (136cm^2)^0.5
V = 13.5cm x 11.66cm
V = 157.41cm^3 (rounded to two decimal places)
Therefore, the volume of the remaining frustum is approximately 157.41cm^3. Thank you for bringing the error to my attention.