Answer: 2pm = 95.6 knots
3pm = 98.6 knots
Step-by-step explanation:
Use the Law of Cosines:
b² = a² + c² - 2ac·cos B
At 2pm, the boat traveled (35 × 3)knots North and (35 × 1)knots NE:
b² = a² + c² - 2ac·cos B
b² = 35² + 105² - 2(35)(105)·cos 65°
b² = 1225 + 11025 - 7350(0.4226)
b² = 9143
b = 95.6
At 3pm, the boat traveled (35 × 3)knots North and (35 × 2)knots NE:
b² = a² + c² - 2ac·cos B
b² = 70² + 105² - 2(70)(105)·cos 65°
b² = 4900 + 11025 - 14700(0.4226)
b² = 9712.5
b = 98.6
