Question 1194940
 Two trains start at the same time from the same point and move along straight railways, which intersect at an angle of 74° 30’ at rates of 30km/h and 40 km/h, respectively. How far apart are they at the end of 45 minutes
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You have 2 sides and the angle between them.
Use the Cosine Law.
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PS  "respectively" is not relevant.