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 10equal sectors as shown in Fig. 12.12. Find:
(i) The total length of the silver wire required
(ii) The area of each sector of the brooch
(i) Total length of wire required will be the length of 5 diameters and the circumference of the brooch
Radius of circle =
mm
Circumference of brooch = 2πr
= 2 * 
* 
= 110 mm
Length of wire required = 110 + 5 × 35
= 110 + 175 = 285 mm
According to the question,
Each of 10 sectors of the circle is subtend36° at the centre of the circle
(ii) Area of each sector =
* 
r2
= 
* 
* (
) * (
)
= 
mm2
9