The ‘tri-’ part of the word triangle means three. A triangle has 3 sides and 3 angles. Interior angles are the angles that are created inside a shape where the sides meet. The interior ...

A scalene triangle has 3 sides of different lengths and 3 unequal angles. An isosceles triangle has 2 sides of equal length. The dashes on the lines show they are equal in length. The angles at ...