Advertisements
Advertisements
Question
Find the radius of the circle whose circumference is equal to the sum of the circumferences of the circles having radius 15 cm and 8 cm.
Advertisements
Solution
For circle with radius = 15 cm
Circumference of circle = 2πr
= `2xx22/7xx15` cm
= `660/7` cm
For circle with radius = 8 cm
Circumference of circle = 2πr
= `2xx22/7xx8` cm
= `352/7` cm
Sum of the circumferences of these two circles
= `660/7"cm"+352/7"cm"=1012/7"cm"`
If the required radius = R cm
Its circumference = 2πR
= `2xx22/7xx"R cm"`
= `44/7"R cm"`
Given, `44/7"R"=1012/7`
⇒ R =`7/44xx1012/7` cm
= 23 cm
∴ Required radius = 23 cm
APPEARS IN
RELATED QUESTIONS
In Fig. 7, are shown two arcs PAQ and PBQ. Arc PAQ is a part of circle with centre O and radius OP while arc PBQ is a semi-circle drawn on PQ ad diameter with centre M. If OP = PQ = 10 cm show that area of shaded region is `25(sqrt3-pi/6)cm^2`.
In Figure, find the area of the shaded region [Use π = 3.14]
The base of a right-angled triangle measures 48 cm and its hypotenuse measures 50 cm. Find the area of the triangle.
In the given figure,
\[\square\] PQRS is a rectangle. If PQ = 14 cm, QR = 21 cm, find the areas of the parts x, y, and z.
Four equal circles, each of radius a units, touch each other. Show that the area between them is `(6/7 a^2)` sq units.
Find the volume and the surface area of the spheres in the following :
Diameter= 6.3 cm
The circumference of a circular field is 308 m. Find is:
(i) Radius
(ii) Area.
The diameter of a circle is 5.6 cm. Find its circumference.
The speed of a car is 66km per hour. If each wheel of the car is 140cm in diameter, find the number if revolution made by each wheel per minute.
Circumferences of two circles are equal. Is it necessary that their areas be equal? Why?
