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The volume of solid a is 792pi, it is a hemisphere plus cyclinder

The volume of solid b is 99pi it is a similar shape to solid a
Calculate the ratio of the surface areas in the form 1:n
The ratio of the radius of the cylinder to the height is 1:3

User Tnull
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To solve this problem, let's start by finding the individual components of solid A.

Let the radius of the hemisphere in solid A be denoted as r, and the height of the cylinder be denoted as h.

The volume of a hemisphere is given by V_hemisphere = (2/3)πr^3, and the volume of a cylinder is given by V_cylinder = πr^2h.

Given that the volume of solid A is 792π, we can set up the equation:

(2/3)πr^3 + πr^2h = 792π

To simplify the equation, we can divide both sides by π:

(2/3)r^3 + r^2h = 792

Now, let's consider solid B. Since it has a similar shape to solid A, the ratio of their volumes is the same as the ratio of their surface areas.

The volume of solid B is given as 99π, so we can set up the equation:

(2/3)r_b^3 + r_b^2h_b = 99

Given that the ratio of the radius to the height of the cylinder is 1:3, we can express h in terms of r as h = 3r.

Substituting this into the equations, we have:

(2/3)r^3 + r^2(3r) = 792

(2/3)r_b^3 + r_b^2(3r_b) = 99

Simplifying the equations further, we get:

(2/3)r^3 + 3r^3 = 792

(2/3)r_b^3 + 3r_b^3 = 99

Combining like terms:

(8/3)r^3 = 792

(8/3)r_b^3 = 99

To isolate r^3 and r_b^3, we divide both sides by (8/3):

r^3 = 297

r_b^3 = 37.125

Now, let's calculate the surface areas of solid A and solid B.

The surface area of a hemisphere is given by A_hemisphere = 2πr^2, and the surface area of a cylinder is given by A_cylinder = 2πrh.

For solid A, the surface area is:

A_a = 2πr^2 (hemisphere) + 2πrh (cylinder)

A_a = 2πr^2 + 2πrh

A_a = 2πr^2 + 2πr(3r) (substituting h = 3r)

A_a = 2πr^2 + 6πr^2

A_a = 8πr^2

For solid B, the surface area is:

A_b = 2πr_b^2 (hemisphere) + 2πr_bh_b (cylinder)

A_b = 2πr_b^2 + 2πr_b(3r_b) (substituting h_b = 3r_b)

A_b = 2πr_b^2 + 6πr_b^2

A_b = 8πr_b^2

Now, let's calculate the ratio of the surface areas:

Ratio = A_a : A_b

Ratio = 8πr^2 : 8πr_b^2

Ratio = r^2 : r_b^2

Ratio = (297) : (37.125)

Ratio = 8 : 1

Therefore, the ratio of the surface areas is 1:8.

User Phynfo
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