# Copy of Circle Investigations

## Investigation 1.

Segment AB is a ___________.

Line CB is a ________________.

What do you notice about the angle where the radius meets the tangent line?

The angle formed between a radius and tangent line of a circle is __________ 90 degrees.

## Investigation 2

Angle CAB is a __________. Choices are: a. b. c.

Angle CDB is a __________. Choices are: a. b. c.

These two angles both intersect the circle at what points? ___ and ___.

Move point B or C. What is the size of angle CAB when the size of angle CDB is 50 degrees? (There may be some roundoff error in the applet.)

What is the size of angle CDB when the size of angle CAB is 80 degrees?

If the size of angle CAB is 60 degrees, what would be the size of angle CDB?

Make a conjecture about the relative sizes of a central angle and an inscribed angle that subtends the same arc on a circle.