IRQ2 - How to solve

prashanth.guru wrote:Please let me how to solve the question in the attached image to arrive at the ans marked in the squares of each column

If they ask for an approximate value, we can just ballpark our answers! We can safely take π to be 3 so that 4πr^2 is 12r^2. Rate is $92 per square meter, close to 90, so the cost is close to 12r^2 times 90, which is 1080r^2.

A 5.50 meter circumference means the radius is 5.5/ (2 π), slightly less than 1 and so is r^2. Therefore, 1080r^2 would be around $1000 or less, pick A.

A 7.85 meter circumference means the radius is 7.85/ (2 π), around 1.3 and so r^2 is around 1.7. Therefore, 1080r^2 would be something near to 2000 and less. Pick C