# Sarin learns Perimeter, Area and Volume in school part 102 (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 Ratio, PercentageShapes and Area.

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

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

You should read the posting on Sarin learns Average Number, Percentage and Charting in school (Math Concept) to understand the concept of Percentage.

Also to read the posting on Sarin learns concept of ratio in school to understand the concept of Ratio.

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

Upper primary school mathematics question UPQ465

In the figure below, the ratio of the area of the rectangle to the area of the triangle is 3 : 5. 25% of the rectangle overlaps with the triangle. The area of the rectangle is 552 cm2. Fine the total area of the uncoloured parts of the figure.

Solution:

The area of the rectangle is 552 cm2

The ratio of the area of the rectangle to the area of the triangle is 3 : 5

3 units = 552

1 unit = 184 cm2

The area of the triangle = 5 × 184 = 920 cm2

25% of the rectangle is overlapped

The area overlapped = 552 × 25% = 138 cm2

The area of the uncoloured region = 552 – 138 + 920 – 138 = 1196 cm2

Alternative Solution:

The area of the rectangle is 552 cm2

The ratio of the area of the rectangle to the area of the triangle is 3 : 5

25% of the rectangle is overlapped

This means ¼ of the rectangle is overlapped

By subdivide 1 unit to 4 sub-units

12 sub-units = 552

1 sub-unit = 46 cm2

3 sub-units for rectangle overlapped

The total unoverlaped sub-units = 32 – 6 = 26

The total area of the uncoloured region = 26 × 46 = 1196 cm2