A lamp shade is in the form of a frustrum of a cone the button ra duis is thrice the top raduis and the height is 14cm the volume of the lamp shade is 763cm find the button of the raduis , the area of the clothes to cover the lamp shade
frustrum?
button?
ra
duis?
raduis?
button of the raduis?
clothes?
Please proofread and correct.
Also include appropriate punctuation and capitalization.
I think you have two cones, same top, same shape, one ending at the top, the other ending at the bottom.
You have the ratio of radii and the difference in volumes. The difference in heights of the two cones is 14cm.
volumetop=1/3 PI*r^2(h)
volumebottom=1/3 pi(2r)^2(h+14)
no subtracting the top from the bottom, you get the volume given. That ought to be enough.
763=1/3 (PI)r^2*(8(h+14)-h)
solve for r, the top radius. Then bottom radius is twice that.
Surface area=PI(rtop+rbottom)/2 * 14
and you have it.
I agree with Ms Sue, you did a sloppy job of proofing if done at all.
To find the bottom radius of the lamp shade, we can use the relationship given in the question.
Let's assume the top radius of the frustrum cone is 'r'. According to the given information, the bottom radius is three times the top radius, so the bottom radius would be '3r'.
Now, let's calculate the volume of the lamp shade using the formula for the volume of a frustrum cone:
V = (1/3) * π * (r^2 + R^2 + (r*R)) * h
Where:
V is the volume of the lamp shade
π is a constant approximated to 3.14
r is the top radius
R is the bottom radius
h is the height of the frustrum cone
In this case, the volume is given as 763 cm^3, and the height is given as 14 cm. Plugging these values into the formula, we get:
763 = (1/3) * π * (r^2 + (3r)^2 + (r*(3r))) * 14
Simplifying this equation, we have:
763 = (1/3) * π * (r^2 + 9r^2 + 3r^2) * 14
763 = (1/3) * π * (13r^2) * 14
763 = (1/3) * π * 182r^2
Now, we can solve this equation to find the value of 'r'.
1) Divide both sides of the equation by (1/3) * π * 182:
763 / ((1/3) * π * 182) = r^2
2) Take the square root of both sides:
√(763 / ((1/3) * π * 182)) = r
After calculating the square root, you will get the value of the top radius 'r'.
Next, to find the area of the cloth needed to cover the lamp shade, we can use the formula for the lateral surface area of a frustrum cone:
A = π * (r + R) * l
Where:
A is the lateral surface area
r is the top radius
R is the bottom radius
l is the slant height of the frustrum cone
To find the slant height, we can use the Pythagorean theorem. The slant height 'l' can be calculated as follows:
l = sqrt(h^2 + (R - r)^2)
Plug in the values for 'h', 'R', and 'r', which are given in the question, and you can find the slant height 'l'.
Finally, substitute the values of 'r', 'R', and 'l' into the formula for the lateral surface area to get the area of cloth needed to cover the lamp shade.