1]A contractor agrees to dig a basement 8mx6mx3m.How many cubic meters of earth will be taken out?2]A rectangular sheet of paper of dimensions 25cmx14cm is revolved along its width to form a cylinder.Find the volume of the cylinder so formed.3]A HOLLOW CYLINDRICAL PIPE IS 1.4m long.Its outer and inner diameters are cm and cm respectively.Find the volume of the metal used in making pipe.

1]A contractor agrees to dig a basement 8mx6mx3m.How many cubic meters

1.	1]A contractor agrees to dig a basement 8mx6mx3m.How many cubic meters of earth will be taken out?2]A rectangular sheet of paper of dimensions 25cmx14cm is revolved along its width to form a cylinder.Find the volume of the cylinder so formed.3]A HOLLOW CYLINDRICAL PIPE IS 1.4m long.Its outer and inner diameters are cm and cm respectively.Find the volume of the metal used in making pipe.
Answer» 1. The earth to be TAKEN out = volume of the basement = 8×6×3 = 144m³ 2. length of sheet = 25cm width of sheet = 14 cm if it is REVOLVED along its width to form a cylinder, HEIGHT = length of sheet = 25cm perimeter = width of sheet = 14 cm $2 \pi r = 14\\2* \frac{22}{7}r=14\\r= \frac{147}{222} =2.23\ cm$ $volume= \pi r^2h= \frac{22}{7}2.23^225=390.73\ cm^3$ 3.length = 1.4 m = 140cm inner DIAMETER( $d_i$ )=10cm inner radius( $r_i$ ) = 10/2 = 5 cm outer diameter( $d_o$ )=12cm outer radius( $r_o$ ) = 12/2 = 6 cm Volume of METAL used = volume of outer cylinder - volume of inner cylinder $V= \pi r_o^2h- \pi r_i^2h\\V= \pi h(r_o^2-r_i^2)\\V= \frac{22}{7} 140(6^2-5^2)\\V= 4840\ cm^3$