1. Circles and Pythagorean Theorem

2. Circle and Radius The radius of a circle is the distance from the center of the circle to any point on the circle, all radii are the same.

3. Tangent Line Conjecture A tangent line is a line that touches the circle at one point call the point of tangency. The Tangent line is perpendicular to the radius at this point. You can now use Pyth Thrm To find sides

4. Inscribe Angle Conjecture If a triangle is inscribed in a circle, with diameter as one side then the other two sides form a right angle.

5. Isosceles Triangle Two radii of a circle will form an Isosceles Triangle. Altitude will cut the opposite side in half, be perpendicular and cut the angle in half.

6. Sector of a Circle This is part of the circle, like a piece of pizza or pie. 1.Find the area of the circle 2.Multiply by the fractional part of the circle, angle of the sector divided by 360

7. Example Find the area of the sector.