Maths: Area question

No very good with maths and have come across this question so could someone help with the answer with a simplified equation please
A piece of lead flashing has to be cut to the shape shown. What is the total area of the lead required in cm2?
(Area of a circle is ϖr2 where r is the radius and ϖ = 3.14)

http://www.pixhost.org/show/2328/16906347_image6.jpg
Thanks
Answer #1
2cm in radius?
Answer #2
Total area = area of rectangle + area of circle
Area of rectangle:
area = width * height
area = 20 * 45
area = 900 cm^2
Area of circle:
area = pi * r^2
r = 10 (diameter / 2)
area = pi * 10^2
area = pi * 100
area ~ 314.159 cm^2
Total area:
Total area = 900 cm^2 + 314.159 cm^2
Total area = 1,214.159 cm^2
Answer #3
Thanks now i just have to get it into my thick head lol