Quadrants: Quarters on a coordinate plane.

1. Terminal side Initial side Vertex Quadrants: Quarters on a coordinate plane. Angle: Two sides joined at a vertex make up an angle ~ Three parts: initial side, terminal side, vertex Standard position: When putting an angle on the coordinate grid, the initial side lays on the positive x axis, and the vertex on the origin Positive Angles: Terminal side moves in COUNTERCLOCKWISE direction Negative Angles: Terminal side moves in a CLOCKWISE direction Degrees: Unit of measurement for interior angle of a circle; 360o total in a circle Radians: Units of measurement for the arc length of a circle circumference: 2π radians total in a circle Converting Between radians ↔ degrees 1.) To convert from DEGREES to radians: Multiply degrees given by 1.) To convert from RADIANS to degrees; Multiply radians given by Coterminal Angles: Let a be an angle measurement, then a and a + 360b are coterminal Let a be a radian measurement, then a and a + 2bπ are coterminal Radians in Quadrants Quadrant I: and 0 - radians Quadrant II: and - radians Quadrant III: and Quadrant IV: and