Section 9.1 and 9.2

9.1 Review of Radicals and Quadratic Equations

Quadratic Formula -

9.2 Introduction to Circles

An arc is made up of two points on a circle and all points of the circle need to connect those two points is a single path. On Circle D, arc BC is a minor arc, and is less than a semicircle. Arc BAC is a major arc, and is more than a semicircle.

Arcs can be measured in two ways, length and degrees. The measure of an arc is congruent to the measure of the angle formed by the radii that determine the points of the arc. (ex. 50 degrees)

To find the length of an arc, set up a proportion.

A sector is part of a disk. (ex. BDC) You also set up a proportion to find the area of a sector.

AB and AC are chords, and angle BAC is an inscribed angle on circle D. The measure of an inscribed angle is half of the arc it intercepts. (ex. angle BAC intercepts arc BC, measure of arc BC is 50, so angle BAC = 25 degrees.)

-Olivia Sheridan