One angle of the triangle is 20 degrees, the other 30 degrees. What is the third angle of a triangle?

One angle of the triangle is 20 degrees, the other 30 degrees. What is the third angle of a triangle? One angle of a triangle is 30 degrees, the other is 15 degrees greater. What is the third angle of a triangle? One angle of a triangle is 2 times less than the second and 3 times less than the third angle. What are the angles of a triangle?

We will use the fact that the sum of the angles of a triangle is 180 °.

If one angle is 20 °, the other 30 °, then the third angle is:

180 ° – 20 ° – 30 ° = 130 °.

If one angle is 30 °, the other is 15 ° larger, i.e. equals 30 ° + 15 ° = 45 °, then the third angle:

180 ° – 30 ° – 45 ° = 105 °.

If the first angle A is twice less than the second, then the second angle is 2 * A. If the first angle A is 3 times less than the third, then the third angle is 3 * A. Then we get:

A + 2 * A + 3 * A = 180 °, 6 * A = 180 °, A = 30 ° and therefore the angles of the triangle are 30 °, 60 °, 90 °.