Yes, you should have a component form and a trigonometric form for the dot product which will allow you to solve for the angle. To the nearest degree, your classmate is correct.
Find the angle between the vectors <2,-4> and <-6,-1>. Round to the nearest whole degree.
Do i use the dot product to fnd the angle? And my classmate got 107 degrees as an answer and I wanted to see if he was correct or not, thanks!