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 = 2π*r*

= 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 = * r^{2}

= * * () * ()

= mm^{2}

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