Find a quarter of the area of a circle with a diameter of 10cm.
To find a part of the area we need the whole area first.
Find the formula for the area of a circle: A= pi x r2
We have been given the diameter so we need to work out what the radius is, half of the diameter so r = 5cm.
Now use the formula for the area to find the area of the whole circle on your calculator: A = pi x 52 = 78.54cm2
The final step is to now find the fraction of the circle that is asked for.
To do this we simply multiply the whole area by the fraction that they want so in this case we need to do 1/4 x 78.54 = 19.64cm2 cm2 (2dp)
Remember not to forget the units and it is good to write down what you have rounded the answer to, in this case 2 decimal places.
