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6-147.
  1. Two logs of radius 80 cm and 20 cm have a single wire around them as shown in the figure below. Find the length of the wire. Hint: ∠ACD and ∠BDC are right angles. Draw a linethrough B parallel to CD meeting AC at E. Homework Help ✎

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Label the drawing!

Line AB = 100 because it is the sum of the radii of both logs.

Then cosθ = 0.6, so θ ≈ 0.927 radians. Thus the wire length around the large log is 80(2π– 2(0.927)) = 354.287 cm.