Tuesday, November 17, 2015

[Pri20151117MSAS] MCQ tactic for the Area of a Hollow Square

Question

Solution 1
     Width of the smaller square  WX = (156 ¸ 4) cm   = 39 cm
     Width of the larger square     AB = (39 + 2´8) cm = 55 cm
     Area = (552 – 392) cm2 = 1504 cm2 
     Ans: (1)

Solution 2
     This is a Multiple Choice Question (MCQ).  Observe that the shaded area is an even number, because it is 8 cm width all around.  Since 1504 is the only even number among the options, (1) is the correct choice.

Remark
     No tedious calculation is needed!

H02. Use a diagram / model
H04. Look for pattern(s)
H09. Restate the problem in another way
H10. Simplify the problem
H11. Solve part of the problem

Suitable Levels
Primary School Mathematics
* other syllabuses that involve areas and perimeters
* anyone who loves his/her brain tickled





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