Question

the area of a circular ring formed by two concentric circles whose radii are 5.7cm
and 4.3 cm respectively is(Take π=3.14)
​

Answer 1

Step-by-step explanation:

Let the radii of the outer and inner circles be r

2

and r

1

respectively; we have

Area=πr

2

2

−πr

1

2

=π(r

2

2

−r

1

2

)

=π(r

2

−r

1

)(r

2

+r

1

)

=π(5.7−4.3)(5.7+4.3)=π×1.4×10 sq. cm

=3.1416×14sq.cm.=43.98 sq. cm