CBSE Class 10-Mathematics: Chapter –12 Areas Related to Circles Part 6

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Question 10:

A brooch is made with silver wire in the form of a circle with diameter 35 mm. The wire is also used in making 5 diameters which divide the circle into 10 equal sectors as shown in figure. Find:

(i) the total length of the silver wire required.

(ii) the area of each sector of the brooch.

Answer:

(i) Diameter

Circumference

Length of 5 diameters ………. (ii)

Total length of the silver wire required

(ii)

The area of each sector of the brooch

Question 11:

An umbrella has 8 ribs which are equally spaced (see figure). Assuming umbrella to be a flat circle of radius , find the area between the two consecutive ribs of the umbrella.

Answer:

Here,

Area between two consecutive ribs of the umbrella

Question 12:

A car has two wipers which do not overlap. Each wiper has a blade of length 25 cm sweeping through an angle of . Find the total area cleaned at each sweep of the blades.

Answer:

Here,

The total area cleaned at each sweep of the blades

Question 13:

To warn ships for underwater rocks, a lighthouse spreads a red colored light over a sector of angle to a distance of . Find the area of the sea over which the ships are warned.

Answer:

Here,

The area of sea over which the ships are warned

Question 14:

Tick the correct answer in the following:

Area of a sector of angle (in degrees) of a circle with radius R is:

(a)

(b)

(c)

(d)

Answer: (D)

Given,

Area of sector