Question

3) Find diameter of a circle whose circumference is 31.4 cm
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Answer 1

As we know that circumference of the circle is given as-
Circumference =2πr
Given:-
Circumference of the circle =31.4cm
∴2πr=31.4
⇒2×3.14×r=31.4
⇒r=5cm
Now again as we know that the area of the circle is given as-
Area =πr
2

⇒ Area =3.14×(25)
2
=78.5cm
2

Hence the radius and area of the circle is 5cm amd 78.5cm
2
respectively.

Answer 2

Answer:

$circumference \: of \: a \: circle \: is \: = \: 31.4cm \\ diameter \: = 2r \\ circumference \: = \: 2\pi(r) \\ therefore \: 2\pi(r) \: = \: 31.4cm \\ \: \pi = \: 3.14 \\ 2(3.14)(r) = \: 31.4 \\ therefore \: 2r \: = \: \frac{31.4}{3.14} \\ 2r \: = \: 10 \\ we \: know \: that \: diameter \: of \: a \: circle \: is \: 2r. \\ therefore \: now \: the \: diameter\: = \: 10cm. \\ hope \: this \: answer \: is \: helpful \\ please \: mark \: as \: the \: brainliest \: answer. \\ please \: thank \: my \: math \: answers \\ have \: a \: great \: day \: ahead.$