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If the area of a circle is 154 cm^{2}, then its perimeter is
Given area of circle=154
⇒area of circle=πr²
=22/7 ×7×7.
=154
so radius of the circle=7cm
perimeter of circle=2πr
=2 ×22/7×7
=44cm
⇒perimeter of the circle=44 cm.
The radii of two circles are 4 cm and 3 cm respectively. The diameter of the circle having area equal to the sum of the areas of the two circles (in cm)
If the circumference of a circle and the perimeter of a square are equal, the
The perimeter (in cm) of a square circumscribing a circle of radius a cm, is
Side of a square circumscribing a circle of radius a cm = diameter of circle = 2a cm
∴ Perimeter of the square = 4 x 2a = 8a cm
The perimeter of a circle is equal to that of a square, then the ratio of their areas is
If the area of a circle is numerically equal to twice its circumference, then the diameter of the circle is
πr^{2}  2πr x 2 ⇒ r = 4 ⇒ 2r = 8 units
The area of the circle that can be inscribed in a square of side 6 cm is
The diameter of a wheel is 1.26 m. The distance travelled in 500 revolutions is
Radius of the wheel = 1.26/2 = 0.63 m
Distance travelled in one revolution
∴ Distance travelled in 500 revolutions
= 500 x 3.96 = 1980 m
The radius of a circle whose circumference is equal to the sum of the circumferences of the two circles of diameters 36 cm and 20 cm is
Diameter of first circle = d_{1} = 36 cm
Diameter of second circle = d_{2} = 20 cm
∴ Circumference of first circle = πd_{1} = 36π cm
Circumference of second circle = πd_{2} = 20π cm
Now, we are given that,
Circumference of circle = Circumference of first circle + Circumference of second circle
πD = πd_{1} + πd_{2}
⇒ πD = 36π + 20π
⇒ πD = 56π ⇒ D = 56
⇒ Radius = 56/2 = 28 cm
If the sum of the circumferences of two circles with radii R_{1} and R_{2} is equal to the circumference of a circle of radius R, then
2π R_{1} + 2πR_{2} = 2πR
⇒ R_{1} + R_{2} = R.
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