Advertisements
Advertisements
प्रश्न
A wire bent in the form of an equilateral triangle has an area of `121sqrt(3)"cm"^2`. If the same wire is bent into the form of a circle, find the area enclosed by the wire.
Advertisements
उत्तर
We know that, Area of an equilateral triangle(A) of side a is A = `sqrt(3)/(4)"a"^2`
Here, A = `121sqrt(3)`
⇒ `121sqrt(3) = sqrt(3)/(4)"a"^2`
⇒ 121 = `"a"^2/(4)`
⇒ 11 = `"a"/(2)`
⇒ a = 22
⇒ 3a = 66cm
The Circumference of a Circle with radius r = 2πr
Here,
66cm = 2πr
⇒ 66
⇒ r = 10.5cm
The Area of a Circle with radius r = πr2
The Area of a Circle with radius 10.5
= `(22)/(7)(10.5)^2`
= 346.5cm2.
APPEARS IN
संबंधित प्रश्न
Find the circumference of the inner and the outer circles, shown in the adjoining figure? (Take π = 3.14)
Find the circumference and area of circle of radius 4.2 cm
Four cows are tethered at four corners of a square plot of side 50m, so that’ they just cant reach one another. What area will be left ungrazed.
The areas of two circles are in the ratio 9 : 4. The ratio of their circumferences is
The circumference of a garden roller is 280 cm. How many revolutions does it make in moving 490 meters?
A canvas tent is in the shape of a cylinder surmounted by a conical roof. The common diameter of the cone and the cylinder is 14 m. The height of the cylindrical part is 8 m and the height of the conical roof is 4 m. Find the area of the canvas used to make the tent.
There are two circular gardens A and B. The circumference of garden A is 1.760 km and the area of garden B is 25 times the area of garden A. Find the circumference of garden B.
The center O of a circle of a radius 1.3 cm is at a distance of 3.8 cm from a given straight line AB. Draw a circle to touch the given straight line AB at a point P so that OP = 4.7 cm and to touch the given circle externally.
Find the area and perimeter of the circles with following: Diameter = 77cm
Circumference ‘C’ of a circle can be found by multiplying diameter ‘d’ with ______.
