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silverysea

Posted: Wed Aug 07, 2013 5:04 pm 

Joined: Fri Mar 04, 2011 2:32 pm Posts: 971

For superselective, do they need to be able to calculate the area of a circle? Tutor did this today but I've not seen it in any test papers tried so far.


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leanmeamum

Posted: Fri Aug 09, 2013 8:47 am 

Joined: Sat Dec 03, 2011 3:14 pm Posts: 688

they give the formula for the area of a circle or the area, if there is a question involving it.
Maybe the tutor covered the topic just to show how it works so it is easy for the child to see understand circles


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silverysea

Posted: Fri Aug 09, 2013 8:56 am 

Joined: Fri Mar 04, 2011 2:32 pm Posts: 971

Ok that does help! It's all about familiarity I guess!


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parent2013

Posted: Mon Aug 12, 2013 10:48 am 

Joined: Mon Aug 12, 2013 9:13 am Posts: 452

The answer unfortunately is "Yes" for superselectives. I have seen numerous examples in private school papers from previous years where this concept has been tested. It is not rocket science and there are only 2 formulas to remember.
Circumference : 2 X Pi X Radius (where Pi is 3.14 or 3 for approximation) OR Pi X Diameter (as Diameter is twice the radius)
Area: Pi X (square of radius)
One example I remember from top of the head is: 1. Ben has a bicycle with a wheel of radius 1m, how much distance it covers in 10 turns
Using Pi = 3, the distance in one turn is the circumference i.e. 2 X 3 X 1 = 6m. Therefore in 10 turns, it will cover a distance of 10 X 6m i.e. 60m.
2. His grandfather "John" has a bicycle with a bigger wheel of radius 1.5m, how much additional distance it covers in 10 turns? Using Pi = 3, the distance in one turn is the circumference i.e. 2 X 3 X 1.5 = 9m. Therefore in 10 turns, it will cover a distance of 10 X 6m i.e. 90m. The answer is "additional" distance i.e. 9060 = 30m.


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