VOLUME AND SURFACE AREA -> IMPORTANT FACTS AND FORMULAE
I. CUBIOD Let length = l, breadth = b and height = h units. Then, 1. Volume = (l x b x h) cubic units. 2. Surface area = 2 (lb + bh + lh) |
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II. CUBE Let each edge of a cube be of length a. Then, 1. Volume = a³ cubic units. 2. Surface area = 6a² sq. units. 3. Diagonal = √3 a units. |
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III. CYLINDER Let radius of base = r and Height (or length) = h Then, 1. Volume = (∏r²h) cubic units. 2. Curved surface area = (2∏rh) sq. units. 3. Total surface area = (2∏rh + 2∏r² sq. units) = 2∏r (h + r) sq. units. |
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IV. CONE Let radius of base = r and Height = h. Then, 1. Slant height, l = √h² + r ² units. 2. Volume = [1/3 ∏r²h] cubic units. 3. Total surface area = (∏rl + ∏r²) sq.units. |
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V. SPHERE Let the radius of the sphere be r. Then, 1. Volume = [4/3 ∏r3] cubic units. 2. Surface area = (4∏r²) sq. units. |
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VI. HEMISPHERE Let the radius of a hemisphere be r. Then, 1. Volume = [2/3 ∏r3] cubic units. 2. Curved surface area = (3∏r²) sq. units. 3. Total surface area = (3∏r²) sq. units. Remember : 1 litre = 1000 cm³. |