Sarin learns Perimeter, Area and Volume in school part 119 (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 Shapes and Area.

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

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

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

Upper primary school mathematics question UPQ576

The figure below is made up of 2 squares of different lengths and 1 rectangle. Find the area of the yellow region.

upq576-1

Solution:

upq576-2

            The area of the triangle with base of 9 cm,

            = 1/2 × 9 × 6

            = 27 cm2

            The area of the triangle with base of 12 cm,

            1/2 × 12 × 3

            = 18 cm2

            The area of the orange shaded square of 3 cm side length

            = 3 × 3

            = 9 cm2

            The area of the rectangle 3cm by 6 cm

            = 3 × 6 = 18 cm2

            The area of the yellow region

            = 27 + 18 – 18 – 9

            = 18 cm2

Alternative solution:

upq576-3

           Redraw the figure as the above rectangle by adding the green and orange blocks.

           The area of the large rectangle

           = 12 × 6

           = 72 cm2

           The area of the yellow region

           = area of the large rectangle – area of the two blue triangle – area of the orange square

           = 72 – 1/2 x 12 x 3 – 1/2 x 9 x 6 – 3 x 3

           = 72 – 18 – 27 – 9

           = 18 cm2

   More Questions on Shape and Area. Click here….

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2 responses »

  1. I think that there is an error near the end: 72 – 1/2 x 12 x 13 – 1/2 x 9 x 6 – 3 x 3
    should be 72 – 1/2 x 12 x 3 – 1/2 x 9 x 6 – 3 x 3

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