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Find the volume, lateral surface area and the total surface area of a cube each of whose edges measures: (i) 7 m (ii) 5.6 cm (iii) 8 dm 5 cm |
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Answer» (i) We have, Length of the edge of the cube = a = 7 cm We know that, Volume of cube = a3 = 73 = 343 m3 Also, Lateral surface area of the cube = 4a2 = 4 × 7 × 7 = 196 m2 Total surface area of the cube = 6a2 = 6 × 7 × 7 = 294 m2 (ii) We have, Length of the edge of the cube = a = 5.6 cm We know that, Volume of cube = a3 = (5.6)3 = 175.616 cm3 Also, Lateral surface area of the cube = 4a2 = 4 × 5.6 × 5.6 = 125.44 cm2 Total surface area of the cube = 6a2 = 6 × 5.6 × 5.6 = 188.16 cm2 (iii) We have, Length of the edge of the cube = a = 8 dm 5 cm = 85 cm We know that, Volume of cube = a3 = 853 = 614125 cm3 Also, Lateral surface area of the cube = 4a2 = 4 × 85 × 85 = 28900 cm2 Total surface area of the cube = 6a2 = 6 × 85 × 85 = 43350 cm2 |
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