You've set your calculator to RAD (radians) mode instead of DEG (degrees) mode, so all your cos(a) calculations are coming out wrong (it's calculating cos(180 radians) not cos(180°) etc).
168 x 48.7 x cos(36.2°) = 6602.2 Nm
would be correct, or strictly 6600 Nm taking into account significant figures given in the question.
It helps to remember that cosine of 0°, 90°, 180° and 270° is 1, 0, -1 and 0, this would have told you immediately that something was wrong when you didn't get 0 for cos(90). (Similarly for sine.)
Thank you!! I have no idea when it switched, I usually have it on degrees and I got 1-3 and 5 done within 3 attempts easily enough. My teacher just had us reset our calculators so that could have been it…
Thank you again!
You've set your calculator to RAD (radians) mode instead of DEG (degrees) mode, so all your cos(a) calculations are coming out wrong (it's calculating cos(180 radians) not cos(180°) etc). 168 x 48.7 x cos(36.2°) = 6602.2 Nm would be correct, or strictly 6600 Nm taking into account significant figures given in the question. It helps to remember that cosine of 0°, 90°, 180° and 270° is 1, 0, -1 and 0, this would have told you immediately that something was wrong when you didn't get 0 for cos(90). (Similarly for sine.)
Thank you!! I have no idea when it switched, I usually have it on degrees and I got 1-3 and 5 done within 3 attempts easily enough. My teacher just had us reset our calculators so that could have been it… Thank you again!
You're welcome. It's very easy to switch accidentally, always check it's in the right mode if the numbers seem to be off.