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Question

Write the given , draw a figure then show the solution.

1. ) A cube has a surface area of 72 mm Find the length of an edge of the cube.

Answer 1

surface area = 6 times the area of one side = 6A = 6s^2 = 72 a cube has 6 sides. each side has area = the edge squared.

s^2 = 72/6 = 12

s = sqr12 = 2sqr3 = about 2(1.732) = 3.464 = length of an edge of the cube