Equilateral, Scalene, and Isosceles Triangles, and Identifying Triangles

Hello Again!

Do you remember last time how we talked about how to tell if a triangle is right, obtuse, or acute? Remember, if it has a 90 degree angle, it is a right triangle, if it has even one angle larger than 90 degrees, then it is obtuse, and if it has all angles smaller than 90 degrees, then it is acute.

Today, I will be telling you how to identify if a triangle is Equilateral, Scalene, or Isosceles.

First, an equilateral triangle. That means that the length of all sides of the triangle is equal. They can be for any triangle, no matter how big or small, as long as all three sides are equal in length. Equilateral triangles look like this.

As a side note, when all three sides are equal, then all three angles are equal as a byproduct. Notice how there is a dash on all three sides? That is to signify that they are all the same length.

Next, an isosceles triangle is a triangle in which two of the sides are equal in length. An isosceles triangle looks like this.

Notice how there is a dash on two of the sides? That is to signify that the two sides are equal lengths.

Finally, a scalene triangle. Those are triangles that do not have the same length on any side. Each of the sides in a scalene triangle is going to be a different length, and the dashes on each side are different. Notice how there is one dash on one side, two dashes on the second side, and three dashes on the third side? That's because they are all different lengths. This is what a scalene triangle looks like.