leanne's answer to Dominic John's Primary 5 Maths Area & Volume Singapore question.
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Given length : breadth = 2:1
Let breadth of each rectangle = x cm
Hence length = 2x cm
We can calculate perimeter( 286cm) by using observation of how many times lengths and breadths appear and additional of those overlapping ones = 6 lengths + 6 breadths + 4 overlapping ones of x cm
= 6 (2x) + 6x + 4(x) = 12 + 10 = 22x
286cm = 22x
Therefore x = 286 / 22 = 13cm
Hence breadth (x)= 13cm
Length (2x) = 13 (2 )= 26cm
Or: calculate each rectangle sides individually
E.g rectangle 1= x +2x+2x = 5x
Rectangle 2= x + x + x + x = 4x
Etc.
until rectangle 5
Area of 1 rectangle= Length multiply by breadth
= 26 (13) = 338 cm 2
Let breadth of each rectangle = x cm
Hence length = 2x cm
We can calculate perimeter( 286cm) by using observation of how many times lengths and breadths appear and additional of those overlapping ones = 6 lengths + 6 breadths + 4 overlapping ones of x cm
= 6 (2x) + 6x + 4(x) = 12 + 10 = 22x
286cm = 22x
Therefore x = 286 / 22 = 13cm
Hence breadth (x)= 13cm
Length (2x) = 13 (2 )= 26cm
Or: calculate each rectangle sides individually
E.g rectangle 1= x +2x+2x = 5x
Rectangle 2= x + x + x + x = 4x
Etc.
until rectangle 5
Area of 1 rectangle= Length multiply by breadth
= 26 (13) = 338 cm 2
Date Posted:
4 years ago
Im primary 5, bit in jc