5.4 Congruent Triangles
Triangle Sums
I.SectionObjectives
- Identify interior and exterior angles in a triangle.
- Understand and apply the Triangle Sum Theorem.
- Utilize the complementary relationship of acute angles in a right triangle.
- Identify the relationship of the exterior angles in a triangle.
II.ProblemSolvingActivity-TriangleSums
- Provide students with a copy of Figure04.01.01
- Students are going to work in pairs with this figure.
- Part one- students need to figure out the angle measures for each of the missing angles.
- Part two- students are going to write down the theorem that helped them to figure out the measure of each
angle. - Allow time for the students to explain their work in small groups.
- Solution:a= 140 ◦Exterior angles in a Triangle Theorem
b= 100 ◦Triangle Sum Theorem
c= 60 ◦Acute Angles Theorem
d= 30 ◦Triangle Sum Theorem or Exterior angles in a Triangle Theorem
Extension- have students draw their own puzzle for others to solve.
III.MeetingObjectives
- Students will identify interior and exterior angles in a triangle.
- Students will apply the Triangle Sum Theorem.
- Students will apply the Exterior Angles Theorem.
- Students will apply the Acute Angles Theorem.
- Students will demonstrate understanding through diagrams and verbal explanations.
IV.NotesonAssessment
- Is the student’s work accurate?
- Can the student talk about why each theorem is appropriate for each angle measure?
- Ask questions and provide feedback when necessary.
Congruent Figures
I.SectionObjectives
5.4. Congruent Triangles