Question

Ngaio makes a dartboard with three concentric circles.
The smallest one has radius 1 metre; the next has radius 2 metres; and the third has radius 3 metres.
She paints the centre circular area red; the next ring she paints blue; and the rest of the board she paints yellow.
Ngaio is not a good darts player and her darts land at random on the board.
If she throws 100 darts, about how many would you expect to land in the yellow region?
What scoring system would you use for Ngaio if you wanted her, on average, to get the same score each time she threw 3 darts?

You can use a calculator and round up to 2 d.p.
Remember to use equation for working out the area of a circle

Answer 1

Answer:

In given radius of area C is 1,B is 2 and A is 3.

Then total area of circular region with radius 3 cm = π(3)2=9π

The area of circular region with radius 2 cm = π(2)2=4π

Then heating area of region A= 9π−4π=5π

Then  probability of a dart hitting board region A= total area of circular discarea of region A=9π5π=0.55

Then probability of a dart hitting board region A=55%.