Category:Isosceles Triangle has Two Equal Angles

This category contains pages concerning Isosceles Triangle has Two Equal Angles:

In isosceles triangles, the angles at the base are equal to each other.

Also, if the equal straight lines are extended, the angles under the base will also be equal to each other.

In the words of Euclid:

In isosceles triangles the angles at the base are equal to one another, and, if the equal straight lines be produced further, the angles under the base will be equal to each other.

(The Elements: Book $\text{I}$: Proposition $5$)