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Answer:
3.694∠127.8°
Step-by-step explanation:
A suitable calculator makes short work of this.
(8; 240°) +(10; 80°) ≈ (3.694; 127.8°)
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If you like, you can add the components of the vectors and figure the magnitude and direction of the result.
a = 8(cos(240°), sin(240°)) ≈ (-4.0000, -6.9282)
b = 10(cos(80°), sin(80°)) ≈ (-1.7365, 9.8481)
r = a + b ≈ (-2.2635, 2.9199)
|r| = √(2.2635² +2.9199²) ≈ 3.69448
∠r = arctan(2.9199/-2.2635) ≈ 127.783°
The resultant is approximately 3.694∠127.78°.