Question

A circular mirror of radius 21cm is surrounded by a circular frame of width 3.5cm. Find the cost of making the frame at rupees 1.50 per cm square

Answer 1

Radius of circular mirror=21 cm
Radius of cirular mirror along with frame=21+3.5=24.5
Area of frame =pi[(24.5)^2-(21)^2]
=22/7×[600.25-441]
=22/7×159.25
=22×22.75
=500.5 sq cm
Cost of 1 sq cm=Rs 1.50
Cost of 500.5 sq cm=500.5×1.50
=Rs 750.75