# CBSE Class 10-Mathematics: Chapter – 12 Areas Related to Circles Part 15 (For CBSE, ICSE, IAS, NET, NRA 2022)

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Question 46:

The radii of two circles are 19 cm and 9 cm, respectively. Find the radius of the circle which has its circumference equal to the sum of the circumference of the two circles

Answer:

circumference of the 1st circle

circumference of the 2nd circle

Question 47:

A car travels distance in which each wheel makes complete revolutions. Find the radius of its wheel

Answer:

Distance travelled by a wheel in complete revolutions

Distance travelled in one revolution

Let r be the radius of the wheel

Question 48:

A sector is cut from a circle of diameter . If the angle of the sector is 1500 find its area.

Answer:

We have,

Diameter

Angle of sector

Area of the sector

Question 49:

In the given figure AOBCA represent a quadrant of area . Calculate the area of the shaded portion. Calculate the Area of the Shaded Portion

Answer:

Required area = Area of quadrant OAB – Area of

## 3 Mark Questions

Question 1:

The cost of fencing a circular field at the rate of per meter is . The field is to be ploughed at the rate of . Find the cost of ploughing the field.

Answer:

Since for ₹ , the length of fencing 1 meter

for ₹ , the length of fencing

Perimeter i.e.. , circumference of the field

Let r be radius of the field.

Area of the field

Total cost of ploughing the field