Find the angle between the given vectors Round to the neares

Find the angle between the given vectors. Round to the nearest ten u = -i + 6j, v = 4i- 4j 0.8 degree 144.5 degree

given vector u = -i +6j , v = 4i -4j

we have to find the dot proudct of u,v

formula for u.v = |u|.|v| cosa ( here a= angle between u and v)

(-i +6j).(4i -4j) = sqrt(1^2 +6^2) . sqrt(4^2 +4^2) cosa

-4 -24 = sqrt(37).sqrt(32) cosa

-28 = 4 sqrt(37) sqrt(2) cosa

cosa = -7/sqrt(37*2)

cosa= -0.813

a = arc cos -0.813

a= 144.5 degree

B) is correct answer