# The lengths of the sides of the triangle are 10,10,12. Find the cosine of the angle between the sides

July 28, 2021 | education

| **The lengths of the sides of the triangle are 10,10,12. Find the cosine of the angle between the sides of the triangle, unequal in length.**

According to the cosine theorem, the square of the side of a triangle can be defined as the sum of the squares of the other two sides minus their doubled product by the cosine of the angle between them. For a given triangle, you can write:

10 ^ 2 = 10 ^ 2 + 12 ^ 2 – 2 * 10 * 12 * cos α, where α is the angle between sides equal to 10 and 12.

240 * cos α = 100 + 144 – 100;

240 * cos α = 144;

cos α = 144/240 = 0.6.

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.