a car wiper has two blades each of lenght 56cm.how much area will they both sweep if each makes an angle of 135 degree while it moves.

Area of sector = Central angle / 360 degree x pie x r square .... in the above angle is 135 degree that is our central angle and assuming the pie = 3.142 and radius we are given with is 56 cm so the equation becomes ( for 1 wiper ) 135/360 x 3.142 x 56 x 56 ( as r square = 56*56 ) = 0.375 x 3.142 x 3136 = 3694.992 cm2 area swept by 1 wiper so area swept by 2 wipers is equal = 3694.992 x 2 = 7389.984 cm2 ...... hope this will be useful