Habs maths 2011 - question 30 can't do it
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Habs maths 2011 - question 30 can't do it
square is 3 units long with 4 identical semi-circles drawn on each edge. semi-circles overlap to create 4 petals which are shaded
the area of each semi-circle is 3.5 square units. work out shaded area
sorry can't draw
the area of each semi-circle is 3.5 square units. work out shaded area
sorry can't draw
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Re: Habs maths 2011 - question 30 can't do it
Area of Square = 3 X 3 = 9 square units
Total Area of all semi Circles = 3.5 X 4 = 14 square units
So, Area of shaded portions = 14 - 9 = 5 square units
Total Area of all semi Circles = 3.5 X 4 = 14 square units
So, Area of shaded portions = 14 - 9 = 5 square units
Re: Habs maths 2011 - question 30 can't do it
thanks for reply
i know i did not draw it but i don't think this is correct
am i wrong twice
i know i did not draw it but i don't think this is correct
am i wrong twice
Re: Habs maths 2011 - question 30 can't do it
Hi Minesh!
I just looked at the diagram (on Habs web site) until I noticed that I could calculate the unshaded area in this way:
Look at two opposing semi circles and imagine them completely shaded. Their area total 3.5 x 2 =7. What's left? It's the two bits opposite each other, which must total 9 - 7 = 2 in area.
There are two of these unshaded pairs of shapes, so the total unshaded area is 2 x 2 = 4.
So the shaded area of the petals must be 9 - 4 = 5 sq units.
Different approach, but I agree with the previously posted answer.
By the way, I wonder if even the Scholarship winners will get this! I think I was just lucky to see the solution visually quite quickly today!
WH
I just looked at the diagram (on Habs web site) until I noticed that I could calculate the unshaded area in this way:
Look at two opposing semi circles and imagine them completely shaded. Their area total 3.5 x 2 =7. What's left? It's the two bits opposite each other, which must total 9 - 7 = 2 in area.
There are two of these unshaded pairs of shapes, so the total unshaded area is 2 x 2 = 4.
So the shaded area of the petals must be 9 - 4 = 5 sq units.
Different approach, but I agree with the previously posted answer.
By the way, I wonder if even the Scholarship winners will get this! I think I was just lucky to see the solution visually quite quickly today!
WH
Re: Habs maths 2011 - question 30 can't do it
Your name is befitting - you work hard
thank you very much for taking the trouble to look at diagram and for clear explanation
thank you very much for taking the trouble to look at diagram and for clear explanation