Question 455481
The lengths of two adjacent sides of a parallelogram are 42cm and 36cm. An angle of the parallelogram is 40 degrees. Find the measure of the longest diagonal to the nearest tenth of a centimeter. (do you use the law of cosines?)
-------------
Draw the picture and you will see that the longest diagonal is opposite
the adjacent angle in the parallelogram, which is 140 degrees.
--------------------------

diag^2 = 42^2 + 36^2 - 2^42*36*cos(140)
diag = 73.32
==================
Cheers,
Stan H.