Question

Devin is making a candle by pouring melted wax into a mold in the shape of a square pyramid. Each side of the base of the pyramid is 30 mm and the height of the pyramid is 18 mm. To get the wax for the candle, Devin melts blocks of wax that are each 8 mm by 6 mm by 5 mm. How many of the wax cubes will Devin need in order to make the candle? Show all formulas and calculations used to arrive at your answer

Answer 1

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Answer:

23

Explanation:

The volume of the square pyramid with base of side length s and height h is ...

V = 1/3s²h

V = 1/3(30 mm)²(18 mm) = 5400 mm³

The volume of a block of wax is ...

V = LWH

V = (8 mm)(6 mm)(5 mm) = 240 mm³

Then the number of blocks of wax required for a candle is ...

(5400 mm³/candle)/(240 mm³/block) = 45/2 blocks/candle

The candle is equal to the volume of 22.5 blocks of wax. We presume Devin will want to melt whole blocks, so ...

Devin needs 23 blocks of wax to make the candle.