Question

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 5 per cm. Also, find the
cost of putting glass at the rate of 31 per cm².​

Answer 1

Answer:

Radius= $\frac{diameter}{2}$

          =$\frac{140}{2}$

          =70 cm

Perimeter of a semi-circle=$\frac{1}{2}$ X2πR

                                          = $\frac{1}{2}$ X 2X $\frac{22}{7}$ X 70

                                          =220 cm

Cost of framing it= 220 cm X 5

                            = $1100

Area of semi-circle= $\frac{1}{2}$ Xπ$R^{2}$

                              =$\frac{1}{2}$ X $\frac{22}{7}$ X 70 X 70

                              =7700$cm^{2}$

Cost of putting glass=7700 X 31

                                  =$ 238700