Question

Find the radius and diameter of a circle whose area is 15400 mm²​

Answer 1

Area=15400mm^2

Now,

Area=pi×r^2

or,15400=22/7×r^2

or,15400×7=22×r^2

or,107800=22r^2

or,107800/22=r^2

or,4900=r^2

or,r=70

Also,

Diameter (d)=r×2

=70×2

=140