In the ABC triangle, the angle with A is 42 degrees, the outer angle at the vertex B is 101 degrees.

In the ABC triangle, the angle with A is 42 degrees, the outer angle at the vertex B is 101 degrees. find the degree measure of the angle C.

A triangle is three points that do not lie on one straight line, connected by segments. In this case, the points are called the vertices of the triangle, and the segments are called its sides.

A rectangular triangle is a triangle in which one corner is a straight line (equal to 90º). The side opposite to the right angle is called the hypotenuse, and the other two are called the legs.

The sum of all the angles of the triangle is 180º:

∠А + ∠В + ∠С = 180º;

∠С = 180º – ∠А – ∠В.

In order to calculate the degree measure of the angle ∠С, you need to find the degree sulfur of the angle ∠В.

Since the sum of the outer and inner angles of a triangle at one vertex is equal to 180º, then:

∠В = 180º – φ;

∠В = 180º – 101º = 79º;

∠С = 180º – 42º – 79º = 59º.

Answer: the degree measure of the angle ∠С is equal to 59º.