 ## Question

primary 5 | Maths | Fractions

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##### Ashley Tan

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What fraction of ABCD is unshaded

Date Posted: 11 months ago
Views: 212
Felicia Goh
11 months ago
16 squares in total, with 4 fully shaded hence remaining (unshaded) = 12/16 = 3/4 (after simplifying)
Concept is a bit like jigsaw puzzle. Try to fit the partially shaded parts to form one shaded square
Ashley Tan
11 months ago
Thank you
Marcus Neale Goh Zheng Jie
11 months ago
Trying to fit the shaded parts together like a jigsaw is not the best method to answering this question because sometimes it is difficult to judge if the area fits. The best way the is to calculate the area of the two unshaded triangles. The big triangle is 0.5x4x4 units^2 and the small triangle is 0.5x2x4 units^2. Then sum the two areas and divide by the area of the whole square 4x4 units^2.
J
11 months ago
Alternatively,

Let length of 1 small square be 1 unit.

Area of shaded triangle = ½ x base x height
= ½ x 2 units x 4 units
= 4 units²

Area of big square
= 4 units x 4 units
= 16 units²

= 4 units² ÷ 16 units²
= ¼ 