Question

find the cost of polishing the top of circular table of diameter 4.2 M if the rate of the polishing is 12 m square

Answer 1

area= πr square
π=22÷7
diameter =2r or radius= d÷2
so=22÷28×4.2×4.2×12

Answer 2

area of circle=
$\pi \: r {}^{2}$
diameter=4.2m
radius=4.2/2=2.1
22/7*2.1*2.1 =22*.63=13.86