A window is in the shape of a semicircle having its diameter as $140 c m$ . Find the cost of framing the window at the rate of $R s . 5 p e r c m$ . Also, find the cost of putting glass at the rate of $R s . 31 p e r c m^{2}$ .

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Solution

Radius of semicircle $= \frac{d}{2} = \frac{! 40}{2} = 70 c m$
Perimeter of semicircle $= π r = \frac{22}{7} \times 70 = 220 c m$
Rate of framing $= R s . 5 per cm$
Therefore,
Cost of framing the window $= 5 \times 220 = R s . 1100$
Also,
Area of semicircle $= \frac{1}{2} π r^{2} = \frac{1}{2} \times \frac{22}{7} \times 70 \times 70 = 7700 {c m}^{2}$
Rate of putting glass $= R s . 31 per {c m}^{2}$
Therefore,
Cost of putting glass $= 31 \times 7700 = R s . 238700$

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A window is in the shape of a semicircle having its diameter as 140 cm. Find the cost of framing the window at the rate of Rs. 5 per cm. Also, find the cost of putting glass at the rate of Rs. 31 per cm2.

Radius of semicircle =d2=!402=70cmPerimeter of semicircle =πr=227×70=220cmRate of framing =Rs.5 per cmTherefore,Cost of framing the window =5×220=Rs.1100Also,Area of semicircle =12πr2=12×227×70×70=7700cm2Rate of putting glass =Rs.31 per cm2Therefore,Cost of putting glass =31×7700=Rs.238700

A window is in the shape of a semicircle having its diameter as $140 c m$ . Find the cost of framing the window at the rate of $R s . 5 p e r c m$ . Also, find the cost of putting glass at the rate of $R s . 31 p e r c m^{2}$ .