triangle angle sum theorem isosceles triangles equilateral triangle
TRANSCRIPT
Triangle Basics, Pythagorean Theorem
TrianglesTriangle Angle Sum TheoremIsosceles TrianglesEquilateral TriangleTriangle Angle Sum Theorem
Definition Isosceles TriangleTick marks indicate that the legs are congruent. They also indicate that the base angles are congruent.
Example 1 Triangle Angle SumSuppose that Angle G measures 40 degrees and Angle GKJ measures 80 degrees, what is the measurement of Angle J?
Example 1 Triangle Angle Sum
Example 1 Triangle Angle Sum
Example 1 Triangle Angle Sum
Example 1 Triangle Angle Sum
Example 1 Triangle Angle Sum
Example 2
Example 2
Example 2
Example 2
Example 2
Example 2
Example 2
Example 2
Example 2
Example 2
Example 2
Example 2
Example 2
Example 2
Example 2
Example 2
Example 2
Example 2
Example 2
Example 2
Example 2
Example 2
Example 2
Example 2
Example 3Compute the measure of the base angles.
Example 3Compute the measure of the base angles.
ACBExample 3Compute the measure of the base angles.Which are the base angles?
ACBExample 3Compute the measure of the base angles.Which are the base angles?
ACB
Example 3Compute the measure of the base angles.Which are the base angles?What may be said about the base angles?
ACB
Example 3Compute the measure of the base angles.Which are the base angles?What may be said about the base angles?
ACB
Example 3Compute the measure of the base angles.Which are the base angles?What may be said about the base angles?
Since is isosceles.
ACB
Example 3Compute the measure of the base angles.Which are the base angles?What may be said about the base angles?
Since is isosceles. By the Triangle Angle Sum Theorem we may write:
ACB
Example 3Compute the measure of the base angles.Which are the base angles?What may be said about the base angles?
Since is isosceles. By the Triangle Angle Sum Theorem we may write:
ACB
Example 3Compute the measure of the base angles.Which are the base angles?What may be said about the base angles?
Since is isosceles. By the Triangle Angle Sum Theorem we may write:
ACB
Example 3, Continued
Example 3, Continued
Example 3, Continued
Example 3, Continued
Example 3, Continued
Example 3, Continued
Example 3, Continued
Example 3, Continued
Recall the question is:Compute the measure of the base angles.
Example 3, Final StepsRecall:
Example 3, Final StepsRecall:
Example 3, Final StepsRecall:
Example 3, Final StepsRecall:
Example 3, Final StepsRecall:
Example 3, Final StepsRecall:
Thus, the measurement of angle A is 62 degrees.
Equilateral TriangleA triangle with three congruent sides is said to be equilateral. Additionally, the following applies to equilateral triangles
HW