How would you describe the angles and sides of an acute, isosceles triangle?

An isosceles must have ##2## equal side lengths and ##2## equal angles only.

An isosceles triangle looks something like:

• Any isosceles triangle has two equal sides, which are both indicated by the variable ##b##. This means that the left side's length ##b## is equal to the right side's length ##b##.
• Any isosceles triangle also has two equal angles, which are both indicated by the line at each angle.

With this information, we can state that for a triangle to be isosceles, it must have ##2## equal side lengths and ##2## equal angles.

If ##b## was not equal to ##b##, then the triangle is not isosceles. Similarly, if the angles were not equal to each other, the triangle is not isosceles.