Sarin learns Perimeter, Area and Volume in school part 91 (Math Question)

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The blog postings are about the Singapore Math. The readers can learn from the postings about Solving Singapore Primary School Mathematics. The blog presents the Math Concept, the Math Questions with solutions that teaches in Singapore Primary Schools. You or the kids can acquire the skill of dealing with the Math Modeling, the Math Problem Solving and the Problem Sum from Lower Primary School to Upper Primary School level after reading the blog postings. This posting is an upper primary school math question on Area and shape.

You can read posting Sarin learns Perimeter, Area and Volume in school(Math Concept) to learn the concept of perimeter and area.

Read also the posting on Sarin learns Shapes and Solids in school (Math Concept) to know about shapes.

Challenge yourself with the question before look out for the given solution‼!

Upper primary school mathematics question UPQ414

The diagram is not drawn to scale. AF = AD and DB = BE. D is the midpoint of AB. If AB = 20 cm, what is the area of the green regions in the figure? (Take Pi = 3.14)

UPQ414-1

Solution:

            Given that AD = DB = AF = BE and C is a point on line FC

            CD = FC = AD = 20 ÷ 2 = 10 cm

            Hence,

            FCDA and CEBD are two identical squares

            ∠ CAD = ∠ CBD = 450

            Arc FD is a quarter of a circle with centre at A and radius = 10 cm

            Arc ED is a quarter of a circle with centre at B and radius = 10 cm

            The area of the white triangle = ½ × 10 × 5 = 25 cm2

            The area of a quarter = ¼ × π × 10 × 10 = 25π

            The area of the green region = 2 × 25π – 2 × 25 cm2 = 50π – 50 = 107 cm2 

 More Questions on Area. Click here….

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