Advertisements
Advertisements
Question
A steel wire, when bent in the form of a square, encloses an area of 121 cm2. The same wire is bent in the form of a circle. Find area the circle.
Solution
Area of a square = ( Side )2
⇒ 121 = ( Side )2
⇒ Side of a square = 11 cm
Now,
The perimeter of a square = Perimeter of a circle
⇒ 4 x Side = Perimeter of a circle
⇒ 4 x 11 = Perimeter of a circle
⇒ Perimeter of a circle = 44 cm
⇒ 2πr = 44 ....( r is radius of a circle )
⇒ r = `44/[2π] = 44/[ 2 xx 22/7]` = 7 cm
∴ Area of a circle = πr2 = `22/7 xx 7 xx 7 = 154 "cm"^2`
APPEARS IN
RELATED QUESTIONS
Find the area of the following circle, given that radius = 14 mm (take `pi = 22/7`).
In a circle of radius 10 cm, an arc subtends an angle of 108° at the centre. what is the area of the sector in terms of π?
If the numerical value of the area of a circle is equal to the numerical value of its circumference , find its radius.
The area of incircle of an equilateral triangle is 154 cm2 . The perimeter of the triangle is
If the area of a sector of a circle bounded by an arc of length 5π cm is equal to 20π cm2, then the radius of the circle
A circular disc of radius 6 cm is divided into three sectors with central angles 90°,120° and 150°. What part of the whole circle is the sector with central angle 150°? Also, calculate the ratio of the areas of the three sectors.
In the given figure, ABCD is a square each of whose sides measures 28 cm. Find the area of the shaded region.
The diameter of a wheel is 0.70 m. Find the distance covered by it in 500 revolutions. If the wheel takes 5 minutes to make 500 revolutions; find its speed in :
(i) m/s
(ii) km/hr.
Find the length of the rope by which a bull must be tethered in order that it may be able to graze an area of 2464 m2
The formula used to find the area of the circle is ________ sq.units
