Question 271646
the diameter of a circular glass frame is 84cm. a 2cm wide metallic border is outside it. find the cost of metal required for bordering the glass frame at Rs.30 per square cm.

There are two steps to solve this problem

find the area of the glass with 2 cm border

find the area of the glass

Subtract the two to get area of the metal portion

Diameter of glass with border = 86 cm

Area = pi*(d^2/4)
 =3.14 *86*86 / 4

5805.86sq. cms.

Diameter of glass is 84 cms
Area of glass is 
Area = pi*(d^2/4)
 =3.14 *84*84 / 4
= 5538.96

5805.86- 5538.96 = 266.9sq. cms is the area of the metal.

The cost will be 266.9* 30 =  Rs. 8007