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(b) a) (i) The ratio of surface area and volume of a sphere is 1 : 3 cm. Find the circumference of the sp (ii) Find the radius of the sphere. (iii) Find the volume of the sphere.



User Avagut
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Final answer:

The radius of the sphere is 9 cm. The circumference is 18(π) cm, and the volume of the sphere is 972(π) cm³.

Step-by-step explanation:

The given ratio of surface area to volume for a sphere is 1:3 cm.

Using the formulae for a sphere:

volume = 4/3 (π) (r)³ and surface area = 4 (π) (r)², we can set up an equation to find the radius of the sphere.

Firstly, we know that the surface area to volume ratio for a sphere is surface area/volume, which is (4 (π) (r)²)/(4/3 (π) (r)³) = 3/r.

Given the ratio is 1:3 cm, we have 1:3 cm = 3:(r) cm, implying r = 9 cm.

Once we have the radius, we can find the circumference of the sphere using the formula

Circumference = 2(π)r, which is 2(π)(9 cm) = 18(π) cm.

Next, for the volume, we substitute r into the volume formula to get

Volume = 4/3 (π) (9 cm)³

= 4/3 (π)(729 cm³)

= 972(π) cm³.

User Lorren
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