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Question 7, I am quite unsure

Question 7, I am quite unsure-example-1
User JPJens
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1 Answer

5 votes

Answer: 137000 cm³

Step-by-step explanation:

formula to find the volume of a hemisphere=
(2)/(3) x πr³

formula to find the volume of a cylinder= πr²×h

both the shapes will have the same radius therefore to get the radius you should divide the diameter by two *you probably already know abt it*

so 46/2= 23 (the radius of both the shapes)

In order to get the height of the cylinder you should subtract the radius of the hemisphere from the total height given as the radius is the same all around the hemisphere **but remember not to mistake the diameter as the radius when subtracting a hemisphere's height from a total height**

height of the cylinder= 90cm- 23cm= 67

Therefore now substitute the values into the formulas and find the volumes of the two shapes separately...

volume of a hemisphere=
(2)/(3) x πr³

=
(2)/(3)× π × 23³

= 25482.5 cm³

volume of a cylinder= πr²×h

= π × 23² × 67 (including the height calculated above)

= 111347.5 cm³

Now add the volumes you found which will give you the volume of water that the tank holds when it if full.

volume of a cylinder + volume of a Hemisphere

111347.5 + 25482.5

136830

137000 cm³ (make sure to estimate the final answer to 3s.f or else you'll lose your accuracy mark)