The sides of the triangle are 6 cm, 8 cm, and 10 cm. Find the cosine of the angle opposite the 6 cm side.
| August 7, 2021 | education
Sides of a triangle:
a = 6 cm; b = 8 cm; c = 10 cm;
Opposite side a lies the angle A. By the cosine theorem:
a² = b² + c² – 2 * b * c * cos A;
cos A = (b² + c² – a²): (2 * b * c);
cos A = (64 + 100 – 36): (2 * 8 * 10);
cos A = 128: 160; cos A = 0.8;
<A = 36.87 °.
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.
