IGCSE Mathematics October/November 2011 paper 4 question 1(c)

Posted Mon 29th April, 2013 @ 06:26 by

Krystal-xuan
Well, I don't know exactly but I will give it a go.

If you imagine the cyclinder unraveled out to form a rectangle (not including the top and bottom circles).

The height is 1.2m , and the length would be the perimeter of the top circle (or bottom for that matter).

So perimeter = 2(pi)r = 0.8pi

Area = Length x height = 0.8pi x 1.2 = (24/25)pi (m^2)

+ it says its open at the top(so you don't have to paint that section) but you will have to paint the bottom section:

therefore area of circle = (pi)r^2 = (pi)(0.4)^2 = (4/25)pi (m^2)

Therefore total area = (24/25)pi + (4/25)pi --> (29/25)pi (m^2)

Its cost $2.3 each m^2 therefore (29/25)pi * 2.3 = $8.38 (3sf)

Answered Sun 5th May, 2013 @ 11:53 by

JackEdited by

Jack on Sun 5th May, 2013 @ 11:53