Question

formula in Ln. surface areas and volumes class 9

Answer 1

SA or TSA=2(lb+bh+hl) sq units.

Lateral surface area of a cuboid=2(l+b)h sq units.

diagonal of a cuboid=root L square + b square +h square units.

Answer 2

Sol: If l, b and h are length, breadth and height of a cuboid, then         •  lateral surface area = 2h (l + b)         •  total surface area of the cuboid = 2(lb + bh + lh)         •  volume = lbh If 'a' is the length of the edge of a cube, then         •  lateral surface area of the cube = 4a2         •  total surface area of the cube = 6a2         •  volume = a3                                                   Curved surface area of a cylinder (CSA) = 2πrh. Total surface area of a cylinder (TSA) = 2πrh + 2πr2 = 2πr(h + r). Volume of a cylinder (V) = πr2h. Base area of the cone = πr2 Curved surface area of the cone = πrl Total surface area of the cone = πrl + πr2 = πr(l + r) Volume of the cone = 1 3 πr2h Surface area of a sphere (A) = 4πr2 Volume of a sphere (V) = 4 3 πr3  Surface area of a hemisphere = 2πr2 Total surface area of a hemisphere = 3πr2  Volume of a hemisphere = 2 3 πr3