Jasper Eng's answer to Coral's Primary 6 Maths Geometry Singapore question.
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Try using Ratio to simplify the question:
Shaded Area to Unshaded circle B
= 25 : 100
= 1 : 4
Shaded Area to Unshaded Whole figure
= 8 : 100
= 1 : 12.5
Now both unshaded figure is 1 unit,
We can combine ratios together:
Unshaded B : Shaded Area : Unshaded whole
= 4 : 1 : 12.5
Unshaded A
= 12.5 - 4
= 8.5 units
Hence Area of A is 8.5 + 1 = 9.5 units
Area of B is 4 + 1 = 5 units
(Add the Shaded parts back to both circle)
9.5 - 5 = 4.5 units more A than B
Percentage More = 4.5/5 * 100%
= 90%
Shaded Area to Unshaded circle B
= 25 : 100
= 1 : 4
Shaded Area to Unshaded Whole figure
= 8 : 100
= 1 : 12.5
Now both unshaded figure is 1 unit,
We can combine ratios together:
Unshaded B : Shaded Area : Unshaded whole
= 4 : 1 : 12.5
Unshaded A
= 12.5 - 4
= 8.5 units
Hence Area of A is 8.5 + 1 = 9.5 units
Area of B is 4 + 1 = 5 units
(Add the Shaded parts back to both circle)
9.5 - 5 = 4.5 units more A than B
Percentage More = 4.5/5 * 100%
= 90%
Date Posted:
3 years ago
Thabk you so much
I made a mistake:
12.5 units is the whole figure,
Hence unshaded is 11.5 units (minus 1)
Hence
Big circle should be 8.5 instead, (minus 1)
Small is 5
So 8.5 - 5 = 3.5 units MORE
3.5 / 5 * 100%
= 70% more //
12.5 units is the whole figure,
Hence unshaded is 11.5 units (minus 1)
Hence
Big circle should be 8.5 instead, (minus 1)
Small is 5
So 8.5 - 5 = 3.5 units MORE
3.5 / 5 * 100%
= 70% more //
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