### Home > PC > Chapter 6 > Lesson 6.4.1 > Problem 6-147

6-147.

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 ✎

Label the drawing!

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

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