Question

The circumference of a circle is eight time the circumference of the circle with radius 12cm. Find its diameter.

Answer 1

Hey friend!

here's ur answer...

given radius is 12cm

circumference of the circle=2πr

=2×22/7×6

=528/7cm

circumference of the new circle, whose circumference is 8 times the circumference of the circle=528/7×8

=4224/7cm

2πr=4224/7cm

2×22/7×r=4224/7cm

44/7×r=4224/7cm

r=4224/7×7/44

r=96cm

hence, diameter=96×2

=192cm

hope this helps...

Answer 2

Circumference of a circle=2πr
radius1=??
radius2=12cm
$2\pi(r1) = 8(2\pi(r2)) \\ 2r1 = 16(r2) \\ 2(r1) = 16(12) \\ r1 = \frac{16 \times 12}{2} \\ r1 = 96 \\ diameter = 96 \times 2 = 196cm$