1. ## [SOLVED] Please check if correct

Barron's SAT Math IIC Page 86

Find the length of the longer diagonal of a parallelogram if the sides are 6 inches and 8 inches and the smaller angle is 60 degrees.

Should it be like

law of cosine c^2=a^2+b^2-2abcos60?

2. c is the longer diagonal ...

$\displaystyle c^2=a^2+b^2-2ab\cos(120)$