Find the angles of an isosceles triangle if the angle at the base is 49 °.

Decision.

1. Since in an isosceles triangle the angles at the base are equal, then in this triangle both angles at the base are equal to 49 °.

2. Knowing that the sum of the angles of any triangle is 180 °, we can find out what the third angle is. To do this, subtract the sum of the two angles at the base from 180 °.

180 – 2 * 49 = 180 – 98 = 82 °.

Answer: The angles of the triangle are 49 °, 82 °, 49 °.