# Sarin learns Perimeter, Area and Volume in school part 86 (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, Math Questions with solutions that teaches in Singapore Primary Schools. You or the kids can acquire the skill of dealing with Math Modeling, Math Problem Solving and 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 Volume.

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 UPQ381

The figure shows a solid that is formed 8 identical cubes. It is coated with a layer of purple paint after formed. The area of the coated faces is 288 cm2.

(a) What of the volume of one cube?

(b) How many more cubes have to be added to the solid to form a cube with a volume of 729 cm3?

Solution:

First to count the number of coated faces and determine the area of one cube

Determine the length of the side of the cube, hence the volume of the cube.

There are six viewing directions for a solid

The coated faces view from the top = 5

The coated faces view from the bottom = 5

The coated faces view from the left = 5

The coated faces view from the right = 5

The coated faces view from the front = 6

The coated faces view from the back = 6

The total number of coated faces = 5 + 5 + 5 + 5 + 6 + 6 = 32

The area of one face = 288 ÷ 32 = 9cm2

The length of the side of a single cube = 3cm

The volume of one cube = 3 × 3 × 3 = 27cm3

To transform the solid to a cube

The total number of cubes needed for 729cm3 solid cube = 729 ÷ 27 = 27

The number of require cubes to add = 27 – 8 = 19

To note: You need to makesure that 27 cubes can be form to a solid cube.