- Students will find relationships between adjacent arcs.
- Students will find relationships between arcs and chords.
IV.NotesonAssessment
- Collect student work.
- Check student work for accuracy.
- Offer feedback/notes as needed.
Chords
I.SectionObjectives
- Find the lengths of chords in a circle.
- Find the measure of arcs in a circle.
II.ProblemSolvingActivity-CircleDilemma
- Here is the problem.
- “Mrs. Watson decided to teach her class about chords in a new way. She began by taking them out to the
elementary school playground where there is a huge circle painted on the ground. Then she drew a straight
line across and marked the center of the circle. Mrs. Watson gave her students a tape measure and asked them
to figure out the hypotenuse of the right triangle.” - “Jeff was puzzled, what right triangle? But Maria wasn’t. She took the tape measure and went to work. Here
is what she found.” - Figure 09.05.01
- “Help Maria finish the problem. What is the measure of the hypotenuse?”
- Have students show their work through a diagram and written explanation.
- Solution:
- Use the Pythagorean Theorem.
- 5^2 + 102 =c^2
- 25+ 100 =c^2
- 125=c^2
- 2 ≈c
III.MeetingObjectives
- Students will find the lengths of chords in a circle.
- Students will find the lengths of the sides of a right triangle.
- Students will use this information in problem solving.
IV.NotesonAssessment
- Collect student work.
- Check student work for accuracy.
- Does the diagram accurately show the given information?
- Is the arithmetic correct?
- Does the written explanation make sense?
- Offer correction/feedback as needed.
5.9. Circles