Troubleshooting Trig Problem 1-5: Confirmation Needed

[s3a]

Homework Statement

The problem along with its solution is attached as Problem 1-5.jpg.

Homework Equations

Trigonometry.

The Attempt at a Solution

Should the 60° angle in Fig. 3 be 30°? Is Fig. 3 supposed to be the exact same thing as Fig. 2 except that the force is moved to be entirely horizontal? I'm just trying to make sure that I'm visualizing things properly so sorry for the probably trivial question. I was confused by the 60° angle and then I noticed that d = 30sin(60°) ≠ 15 inches and that if I assumed that Fig. 3 was the exact same thing as Fig. 2 with the force relocated then d = 30sin(30°) = 15 inch which makes sense to me. I'm just looking for a confirmation unless I am wrong, then I am looking for a correction.

Any input would be highly appreciated!
Thanks in advance!

 

[gneill]

Yes, it looks as though they've used the wrong figure; the angle should be 30° to match the rest of the example. Interestingly, they've patched in the correct result even though the calculations are incorrect. Note, for example, that they arrive at length d = 15 inches using d = 30 sin(60). Well sin(60) is not 1/2; sin(30) is.

 

[s3a]

Thank you.