In triangle ABC BC = √17, AC = 3√7, outside angle at vertex C = 120. Find AB
| August 9, 2021 | education
The sum of the outer and inner angles is 180 °, hence:
∠С = 180 ° – 120 ° = 60 °
To calculate the side AB, we use the cosine theorem:
AB² = BC² + AC² – 2 * BC * AC * cos (∠С)
cos 60 ° = 1/2
AB² = (√17) ² + (3 * √7) ²- 2 * √17 * 3√7 * (1/2)
AB² = 17 + 63 – 3√119
AB² = 80 – 3√119
AB = √ (80 – 3√119)
Answer: AB = √ (80 – 3√119)
One of the components of a person's success in our time is receiving modern high-quality education, mastering the knowledge, skills and abilities necessary for life in society. A person today needs to study almost all his life, mastering everything new and new, acquiring the necessary professional qualities.
