Angles of the parallelogram which is given in the problem are:α = 49° + 17 °= 66°
β = 180° - 66° = 114°
x - length of the longest side of the parallelogram;
Use the Sine Law:x / sin 49° = 20/ sin 17°
x / 0.7547 = 20 / 0.2924
0.2924 x = 15.094
x = 15.094 : .2924
x = 51.62 is the longest side of the parallelogram.