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The diagram shows a solid shape. The shape is a cone on top of a hemisphere. 18 cm 30 cm Volume of a cone = Arh Volume of a sphere == nr³ The height of the cone is 30 cm. The base of the cone has a diameter of 18 cm. The hemisphere has a diameter of 18 cm. The total volume of the shape is k cm³, where k is an integer. Work out the value of k.​

The diagram shows a solid shape. The shape is a cone on top of a hemisphere. 18 cm-example-1

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The value of k obtained by summing the volumes of the cone and the hemisphere is k = 1296

The steps used to find the value of k are as follows;

The radius of the cone, r = 18 cm/2

r = 9 cm

Volume of the cone, V = (1/3) × π × r² × h

h = 30 cm

Therefore; V = (1/3) × π × 9² × 30

V = 810·π cm³

Volume of the hemisphere = (4/3) × π × r³/2

r = 9 cm

Therefore; Volume of the hemisphere = (4/3) × π × 9³/2

(4/3) × π × 9³/2 = 486·π

Volume of the hemisphere = 486·π cm³

Volume of the composite figure = (810 + 486)·π cm³

Volume of the composite figure = 1296·π cm³

The total volume of the shape = k·π cm³

Therefore; k·π = 1296·π

k = 1296

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