Chapter 4's Top 5 Concepts

Chapter 4 = TRIANGLES!!!! ...remember all triangles = 180 degrees and to find the missing side of a right triangle, use the formula, a² + b² = c²

Postulates and Theorems

• HL ((hypotenuse leg)) - if the hypotenuse and leg of one right triangle are congruent to the hypotenuse and corresponding leg of another right triangle, then the two right triangles are congruent.
• If two sides of a triangle are congruent, then the angles opposite those sides are also congruent.
• If a triangle is equilateral ((all sides equal)), then it is eqiuangular ((all angles equal)). If a triangle is equiangular, then it is equiangular.

Exterior Angle Formula

• the exterior angle of a triangle is equal to the sum of the 2 non-adjacent interior angles.
• The two acute angles of a right triangle are complimentary.
• example : If one non-adjacent interior angle = 72 degrees and the other = 39 degrees, then the exterior angle = 111 degrees.

Vertex of a triangle

• Where two sides of a triangle meet. There are 3 vertices in a triangle.