Sarin learns Perimeter, Area and Volume in school part 46 (Math Question)

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The blog postings are about the Singapore Math. The readers can learn from the postings on Solving Singapore Primary School Mathematics. You or your kids can learn dealing with Math modeling, Problem Sum from Lower Primary School to Upper Primary School level in Singapore school. This posting is a primary school math question on area.

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

Read also the posting on Sarin learns Shapes and Solids in school (Math Concept) to know about shapes and the posting on Sarin learns Lines and Angles (Math concept) to understand the concept of lines and angles.

Upper primary school mathematics question UPQ158

AD is equal to AG. A is the mid-point of EF. CJ is ¼ of JH. EFHJ is 200 cm2. If DJC is 18 cm2, find the unshaded area DAGHJ.

Solution:

CJ is ¼ of JH

We can sub-divide the unshaded area DGHJ to triangles with equal height and equal length with area of 18cm2

There are 8 small triangles to form the unshaded area DGHJ

The unshaded area DGHJ = 8 × 18 = 144 cm2

The area EFGD = 200 – 144 = 56 cm2

The unshaded area EAG = 56 ÷ 2 = 28 cm2

The unshaded area DAGHJ = 144 + 28 = 172 cm2