Find the resultant vector.

1) A force of 35 grams and 45 grams applied at right angles.
57.009 g at 52° with respect to the 35 kg force
2) Velocities of 400 mph due north and 500 mph due east.
640.31 mph at 51° with respect to the 400 mph force
3) Displacements of 90 meters due north and 70 meters due west
114.02 m at 38° with respect to the 90 m force
4) Forces of 650 kg and 175 kg at an angle of 114° with each other.
673.15 kg at 114° with respect to the 175 kg force
Are these correct?

All are correct except the last one.

you will need the cosine law,
r^2 = 650^2 + 175^2 - 2(650)(175)cos175°
= 545657.5863
r = appr 738.69

remember cos 114° is negative, so the 2abcosØ gets added, this is a common error with obtuse angles and the cosine law