# Prologue: Principles of Problem Solving - Problems: 7

1.9163715 metre of more ribbon is needed, which is equal to 6.28730807087 ft.

#### Work Step by Step

Circumference of the Earth is $2×\pi×(6.38 × 10^{6}m)$. Which is equal to 40 086 722.26 metres. The circumference of the Earth when 1ft(0.305m) is added to the radius is $2×\pi×((6.38 × 10^{6}m) + 0.305m)$. Which is equal to 40 086 724.18 metres. Therefore, the difference is the additional ribbon reqiured, which is $40 086 724.18m - 40 086 722.26m =1.9163715m$. Which is equal to 6.28730807087 ft.

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