Find the length of the diagonal ,d, of the parallelogram below to the nearest inch.

Question

Angle A=130 degree , side b =6in , side c =12in

Answer 1

Draw a parallelogram with angles of 130° and 50°. Then draw a line connecting the two 50° angles. This is the diagonal we are going to find first. We will use the Law of Cosines: c=√(a²+b²-2ab*cos(y)). We will use these values: c=unknown diagonal, a=6; b=12, y=130. We get that the diagonal is about 16.51 inches.

No let's find the other diagonal. Draw it in. We will again use the Law of Cosines, with a=6, b=12, and y=50. This diagonal is about 9.35 inches.