Advertisements
Advertisements
Question
Find the radius and area of a circle, whose circumference is :
(i) 132 cm
(ii) 22 m
Advertisements
Solution
(i)
Circumference of circle = 132 cm
2πr = 132
`2 xx 22/7 xx r = 132`
`r = (132 xx 7)/(2 xx 22)`
`r = 21`cm
∴ Area of circle = `pir^2`
= `22/7 xx 21 xx 21`
= 1386 cm2
(ii)
circumference of circle = 22 m
∴ `2pir = 22`
`2 xx 22/7 xx r = 22`
`r = (22 xx 7)/(2 xx 22)`
r = `7/2`
r = 3.5 m
Area of circle = `pir^2`
= `22/7 xx 3.5 xx 3.5`
= 38.5 m2
APPEARS IN
RELATED QUESTIONS
Prove that the area of a circular path of uniform width h surrounding a circular region of radius r is `pih(2r+h)`
In the following figure, ABC is a right angled triangle in which ∠A = 90°, AB = 21 cm and AC = 28 cm. Semi-circles are described on AB, BC and AC as diameters. Find the area of the shaded region.
If a wire is bent into the shape of a square, then the area of the square is 81 cm2. When wire is bent into a semi-circular shape, then the area of the semi-circle will be ______.
A circular park has a path of uniform width around it. The difference between the outer and inner circumferences of the circular path is 132 m. Its width is
If the sum of the areas of two circles with radii r1 and r2 is equal to the area of a circle of radius r, then \[r_1^2 + r_2^2\]
ABCD is a square of side 4 cm. If E is a point in the interior of the square such that ΔCEDis equilateral, then area of Δ ACE is
In the given figure, PSR, RTQ and PAQ are three semicircles of diameter 10 cm, 3 cm and 7 cm respectively. Find the perimeter of shaded region. [Use π= 3.14]
The length of an arc of a circle, subtending an angle of 54° at the centre, is 16.5 cm. Calculate the radius, circumference and area of the circle.
In the given figure, the sectors of two concentric circles of radii 7 cm and 3.5 cm are shown. Find the area of the shaded region.
Two circles touch each other externally. The sum of their areas is 58πcm2 and the distance between their centres us 10cm. Find the radii of the two circles.
