Question 1092750

Plz help me to do this sum :-  The diameter of base of a chimney is 80 CM  and hieght is 12.5 m. What will be the cost of painting this chimney from outside at the rate of Rs 140  per square metre? π=3.14
(Plz reply me fast. It's argent.) 
<pre>You're being asked to find the surface area of the chimney and then the cost to paint this surface area.
As is obvious, the chimney is in the shape of a cylinder, but only the OUTSIDE of the cylinder is needed. This formula is: {{{pi * D * h}}}, with D being the diameter, and h, the height of the cylindrical chimney.
Now, the diameter is in cm (80 cm = .8 m), but the height is in meters, and the cost is also in meters. Therefore, it's best to keep all units in METERS.
We then get OUTSIDE SURFACE AREA as: {{{pi * (.8)(12.5)}}}, and with the cost being Rs 140 per sq meter, we get: {{{highlight_green(matrix(1,5, 3.14(.8)(12.5) * Rs, 140, "=", Rs, "4,396"))}}}
IGNORE anyone who says otherwise!!