How do you find the diameter from a circumference of 20?

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Answer 1 · 2016-01-06T15:50:10

$d i a m e t e r = 6.36 c m$ $diameter =6.36 cm$

The circumference of the circle is $= 20 c m$ $=20 cm$
(note: assuming units to be in cm)

The formula for circumference of circle $= 2 π r$ $=2pir$

$r = r a d i u s, π = \frac{22}{7}$ $r= radius, pi = 22/7$ (constant)

$2 π r = 20$ $2 pi r = 20$

$2 \times \frac{22}{7} \times r = 20$ $2 xx 22/7 xx color(blue)(r) = 20$

$r = 20 \times \frac{7}{22} \times \frac{1}{2}$ $color(blue)(r) = 20 xx 7/22 xx 1/2$

$color(blue)(r) = cancel20 xx 7/22 xx 1/cancel2$

$color(blue)(r) = 10 xx 7/22$

$color(blue)(r) = 70/22$

So the diameter $= 2 xx radius$

$= cancel2 xx 70/cancel22$
$=70/11$

$diameter =6.36 cm$