SOLUTION: A man-hole on a drainage pipe is covered with an iron-plate, which is of the shape of a square of side 12.5 cm. From this iron-plate, a circular disc of diameter 7 cm is painted i

Algebra ->  Surface-area -> SOLUTION: A man-hole on a drainage pipe is covered with an iron-plate, which is of the shape of a square of side 12.5 cm. From this iron-plate, a circular disc of diameter 7 cm is painted i      Log On


   

Question 1024685: A man-hole on a drainage pipe is covered with an iron-plate, which is of the shape of a square of side
12.5 cm. From this iron-plate, a circular disc of diameter 7 cm is painted in black colour. The remaining
part is painted with blue colour paint. Find the blue paint required, if 1cm2 requires 0.8 g of paint. (Use
22
7
p 5 )
Answer by macston(5194) About Me  (Show Source):
You can put this solution on YOUR website!
side=12.5cm; r=(1/2)diameter)=3.5cm
.
Area_of_square=%28side%29%5E2
.
Area_of_circle=pi%28r%5E2%29
.
(Area of square)-(area of circle)=(area of blue)
.
%2812.5%29%5E2-pi%283.5%29%5E2=%28area_of+blue%29
.
156.25cm%5E2-38.48cm%5E2=%28area_of+blue%29
.
117.77cm%5E2=%28area_of_blue%29
.
117.77cm%5E2%2A0.8%28g%2Fcm%29=94.21g
.
I have no idea what:
22
7
p 5)
means.
.