- Then fold it in half again.
- This way you have a circle that has been divided.
- Finally, trace each line of the folds of the circle so that they can be seen.
- Then glue the circle with its lines to a piece of white paper.
- Have the students choose one pair of lines to extend outside the circumference of the circle.
- Then have students work in small groups to figure out the measures of each of the angles created by the
different folds of paper. - Some students may have folded their circles differently.
- This is alright as long as the students are going to work together.
- Ask them to work together on figuring out the angle measures.
- Allow students time to work and then to share their work when finished.
III.MeetingObjectives
- Students will find the measures of angles formed by chords, secants and tangents.
- Students will work in groups to figure out the different angle measures.
- Students will share their work when finished.
IV.NotesonAssessment
- Walk around as students work and offer assistance as needed.
- If students are having difficulty, remind them to refer back to the text.
- Collect student work when finished, and assess student understanding based on the accuracy of student work.
- Offer feedback and correction as needed.
Segments of Chords, Secants and Tangents
I.SectionObjectives
- Find the lengths of segments associated with circles.
II.ProblemSolvingActivity-Criss-CrossApplesauce
- Here is the problem.
- “Jack and Andy decided to play a game called Criss Cross Applesauce in the school yard. They each took a
jump rope and ran across the circular playground. Their ropes crossed at one point. They wondered who had
a longer rope. Using this diagram, help them to figure this out.” - Figure 09.08.01
- Allow time for students to share their work when finished.
- Solution:
- The produce of one line segment is equal to the product of the other line segment.
- Therefore, we can solve for the missing segment of the line by writing an equation and multiplying.
- 12x= ( 6 )( 10 )
- 12x= 60
- x= 5
- One rope is 16 feet long.
- One rope is 17 feet long.
- The boy with the 17 foot long rope has the longer rope.
- Extension- What happens when an 18 foot rope is added to the mix- where does this rope cross the circle?
Does it intersect with the other two ropes?
5.9. Circles