A sheet is $11 c m$ long and $2 c m$ wide. Circular pieces $0.5 c m$ in diameter are cut from it to prepare discs. Calculate the number of discs that can be prepared.

Open in App

Solution

Length of sheet $= 11 c m$
Breadth of sheet $= 2 c m$
Area of sheet = length $\times$ breadth = $11 \times 2 = 22$ $c m^{2}$
Radius of the disc = $\frac{d}{2}$ = $\frac{0.5}{2}$ = $0.25 c m$

Area of the disc = $π r^{2}$ = $\frac{22}{7} (0.25)^{2}$ = $\frac{1.375}{7}$ = $0.196 c m^{2}$
Thus, number of discs = $\frac{A r e a o f s h e e t}{A r e a o f d i s c}$ = $\frac{22 c m^{2}}{0.196 c m^{2}}$ $= 112$ discs

Suggest Corrections

Similar questions

A sheet is 11 cm long & 2 cm wide. Circular pieces 0.5 cm in diameter are cut from it to prepare discs. Calculate the number of discs that can be prepared.

Q. A sheet is 11 cm long and 2 cm wide. Squares of side 0.5 cm are cut from it. Calculate the total number of such squares that can be obtained.

Q. A metal cylinder with height

10 c m

and the diameter of base

70 c m

is melted to make a number of small discs with radius

1 c m

and thickness

0.5 c m

. How many such discs could be made from the cylinder?

Q. A circular disc is to be made using iron and aluminium. To keep its moment of inertia maximum about a geometrical axis, it should be so prepared that

Join BYJU'S Learning Program

A sheet is 11 cm long and 2 cm wide. Circular pieces 0.5 cm in diameter are cut from it to prepare discs. Calculate the number of discs that can be prepared.

Length of sheet =11 cmBreadth of sheet =2 cmArea of sheet = length × breadth = 11×2=22 cm2Radius of the disc = d2 = 0.52 = 0.25 cmArea of the disc = πr2 = 227(0.25)2 = 1.3757 = 0.196 cm2Thus, number of discs = Area of sheetArea of disc = 22 cm20.196 cm2 =112 discs

A sheet is $11 c m$ long and $2 c m$ wide. Circular pieces $0.5 c m$ in diameter are cut from it to prepare discs. Calculate the number of discs that can be prepared.