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ML Aggarwal Solutions Class 9 Mathematics Solutions for Mensuration Exercise 16.3 in Chapter 16 - Mensuration
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Find the radius and area of a circle if its circumference is 18π cm.
Answer:
Consider the radius of the circle = r
Circumference = 2 πr
We know that
2 πr = 18π
So we get
2r = 18
r = 18/2 = 9 cm
Here
\begin{aligned} &\text { Area }=\pi \mathrm{r}^{2}\\ &\text { Substituting the value of } r\\ &=\pi \times 9 \times 9\\ &=81 \pi \mathrm{cm}^{2} \end{aligned}
Video transcript
"hello and welcome my dear students
i am rishabh the math pseudonym leader
and i'm here a new question it is find
the radius and the area of circle
if its circumference is 18 pi
centimeters
so without wasting much time let's have
a look at the solution
so let's
radius of circle vr
and we know that circumference is
2 pi r
we know that we have been given
circumference as 18 pi centimeters
so 2 by r is equals to 18 pi
which means solving it further we get r
as 18 by 2 which is nothing but
9 centimeter
so we have found out the radius and we
are left with area
so area of circle
is nothing but pi r square
which is nothing but pi into 9 into
9 which is nothing but equals to
81 pi centimeter square
so i hope my students got this question
well do subscribe our channel for the
regular updates
see you next time bye"
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