An aluminium plate is a rectangle measuring by

MATHEMATICS · Multi-part · GCSE · Mathematics · Geometry and Measures · Geometry and Measures

Problem

An aluminium plate is a rectangle measuring 25 cm25\,\text{cm} by 18 cm18\,\text{cm}. Three identical circular holes, each of diameter 4 cm4\,\text{cm}, are drilled along the longer side at equal spacing. (a) Calculate the total area removed by the three circular holes. (b) Determine the area of aluminium left in the plate after the holes are drilled. (c) The plate is 0.4 cm0.4\,\text{cm} thick and the density of aluminium is 2.7 g cm−32.7\,\text{g cm}^{-3}. Find the mass (in grams) of the remaining plate, correct to one decimal place.

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