# Parallelogram OPQR is such that OP=[-7,24] and OR=[-8,-1] determine the acute angle between the diagonals OQ and RP.

I'm just really stuck on this question I only found the magnitude of OP = 25 and RP=√65

Hint: Determine the vectors representing OQ and RP, then take the Dot product of them using the $$2$$ different standard definitions (with one involving the angle between the vectors), and then compare these $$2$$ results. I trust you can finish the rest yourself.