Find the angle between the lateral sides of an isosceles triangle if the angle at the base = 40 degrees; 64 degrees; 80 degrees.

1)

Let us determine what the angle between the sides will be equal to when it is known that the angle at the base is 40 °:

180 – 40 * 2 = 100.

Answer: This angle will be 100 °.

2)

Let us determine what the angle between the sides will be equal to when it is known that the angle at the base is 64 °:

180 – 64 * 2 = 52.

Answer: This angle will be 52 °.

3)

Let us determine what the angle between the sides will equal when it is known that the angle at the base is 80 °:

180 – 80 * 2 = 20.

Answer: This angle will be 20 °.