This blog is managed by Song Hock Chye, author of Improve Your Thinking Skills in Maths (P1-P3 series), which is published and distributed by EPH.

Sunday, February 03, 2008

Math Question on Area

The diagram below is made up of 3 squares. Find the area of the shaded area.







Solution






Area of shaded area is

Area of triangle ADC – Area of triangle BGC + Area of triangle EFG

Area of triangle ADC
½ x 16cm x 14cm = 112 square cm

Area of triangle BGC
CG = 6 cm because EG = EF = 2 cm
Therefore area = ½ x 6cm x 6cm = 18 square cm

Area of triangle EFG
½ x 2cm x 2cm = 2 square cm

Therefore area of shaded area is
(112 – 18 + 2) square cm
= 96 square cm (Answer)

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