Question

drill 3 cm diameter 6 holes in 6cm×12cm plate.what about the area of rest part of plate?

Answer 1

According to question

Length of plate    L = 12 Cm
Breadth of Plate  B = 6 Cm

Thus   Area of Plate  = L * B = 12 * 6  = 72

Area of cross section of one hole = pi r^2 = 3.14 * 9 /4
                                                                  = 7.065 Cm^2
So  Area of 6 holes  = 7.065 * 6 = 42.39 Cm^2

Thus   Area left = 72 - 42.39 = 29.61 Cm^2