Question

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

Answer 1

The area of the plate = 6 x 12 = 72cm²

Finding the area of the holes:
Radius of the hole = 3/2 = 1.5cm

Area of the 6 holes = 6 x 22/7 x 1.5² = 42.43 cm²

The area of the rest part of the plate = 72 - 42.43 = 29.57cm²

Answer 2

According to question

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

Thus Area of plate = 12 * 6
                               = 72 Cm^2

Diameter of one hole = 3 Cm
Thus radius of one hole  r = 3/2 Cm
So

Area of one hole = pi r^2  = 9/4 pi
Thus Area of 6 holes = 6 * 9/4 pi = 27/2 pi = 42.39 Cm^2

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