Answer:
|-5i+10j| = 5√5 ≈ 11.18
∠(-5i+10j) ≈ 116.57°
Explanation:
The magnitude is given by the Pythagorean theorem:
|-5i+10j| = √((-5)² +10²) = √125 = 5√5
The direction is found using the arctangent function. The angle is a second-quadrant angle.
∠(-5i+10j) = arctan(10/-5) ≈ 180° -63.43° = 116.57°