form 3 circles

1. Circle Investigations
You need....
1. A problemhalved?
1. Draw a circle with a radius of 4cm. Mark the centre.
2. Draw the diameter of the circle to form 2 semi-circles
3. In one half, mark any point (x) on the circumference and draw lines from each end of
the diameter to that point
4. Measure the angle you have created. Repeat the process in the second half of your
circle
You now have two triangles. Compare your results with your colleagues
Q: What can you say about the triangle formed in a semi-circle?
2. Beam me up, Scotty....
1. Draw a circle with a radius of 4cm. Mark the centre.
2. Mark two points a and b and draw lines firstly to the centre and then to the
circumference (points c and d)
3. Measure angle acb. Measure angle adb
What relationship can you spot between your two angles? Compare the angles you have created with your
colleagues.
Q: What can you say about the angle at the centre and angle at the circumference?
3. Crowning Glory?
1. Draw a circle with a radius of 4cm.
2. Mark three points a, b and c anywhere in the top half of the circumference
and then points e and f in the bottom half, again on the circumference
3. Draw 2 straight lines each from a, b, and c to points e and f. (six lines in
total)
4. Measure the three angles eaf, ebf and ecf.
Compare the measurements of your three angles with your colleagues.
Q: What can you say about the relationship between the three angles?