Final answer:
Triangles can be identified based on their angles or sides, and these distinctions are important for understanding their properties and relationships.
Step-by-step explanation:
A triangle can be identified based on its angles or sides.
a) Equilateral triangles have all three angles equal and all three sides equal. Isosceles triangles have two angles equal and two sides equal. Scalene triangles have all three angles unequal and all three sides unequal.
b) Acute triangles have all three angles less than 90 degrees. Obtuse triangles have one angle greater than 90 degrees. Right triangles have one angle equal to 90 degrees.
c) Pythagorean theorem relates the lengths of the legs of a right triangle with the hypotenuse. Congruent triangles have the same shape and size. Similar triangles have the same shape but different sizes.
d) Exterior angles of a triangle are formed by extending one side of the triangle. Interior angles are the angles inside the triangle. Regular triangles have all three angles equal and all three sides equal.