2Drawing Activity It is 90o Draw a circle. Plot a point on the circle. Draw a radius from the center to the point on the circle.Draw a segment tangent to the circle through that point.What do you notice about the angle formed by the radius and the tangent segment?It is 90o
3If OR = 12 and OT = 16, then RT = ?If m∠OTR = 45o, and RT = 4, then OT = ?20Hint: Use Pythagorean Theorem… Even better see if it’s a Pythagorean Triple!R is the center of the circle.It’s a Special Right Triangle …It is a 3, 4, 5 triangle (multiple of it) so x = 20 because each side increased by 4x.124x16x45o
4Activity #2 Draw another circle. Plot a point outside of the circle. Draw two tangents from the point to the circle. (only hit the circle once from each tangent)What do you notice about the lengths of the two tangents?The lengths are equal.
5The following shows tangents and circles. Find the missing values. y = 7.94x = 7.94z = 7.94
6Tangent LINES Circles can have common tangent LINES. Common internal tangent line: intersects the segment joining the centers.Common external tangent line does not intersect the segment joining the centers.
7Tangent CIRCLESTangent circles are coplanar circles that are tangent to the same line at the same point.Internally tangentExternally tangent
8How many common external tangents can be drawn? 1)2
9How many common internal tangents can be drawn? 2)1
10There is a difference between TANGENT LINES and TANGENT CIRCLES! Remember!There is a difference between TANGENT LINES and TANGENT CIRCLES!