SAT circles

An anhole whose vertex is at the ceneter of the circle and whose sides are radii that intersect the circle

an angle with its vertex on the circle and whose sides are chords of the circle

A central angle is twice the angle measure of inscribed angles. The inverse applies as well: A.n inscribed angle is always half the masure of the central angle that intercepts the same arc.

a line from the center of the circle to any point on the circ;e

a line that passes through the center and connects two points on the cirlce (twice the radius)

a line segment that connects two points on the circle, but does not need to go through the center.

a line that touches the circle at exactly one point and does not cross into the circle

the tangent line forms a right anlge (90 degrees) with the radius at the point of tangency. this

1. Find the point og tangency. this is the point where the line touches the circle 2. Find the radius at that point: Draw a line from mthe center of the circle to the point of tangency. 3. Find the slope of the radius: use the slope formula where (x1, y1) is the center and (x2, y2) is the point of tangency. 4. Take the opposite reciprocal of the radius’ slope: this gives you the slope of the tangent line, because a tangent is perpendicular to the radius. EX: if the radius slop is 2/3, then the tangent slope is -3/2

(x - h)^2 + (y - k)^2 = r^2

(h,k)

arc,length = \frac{\theta}{360} \cdot 2\pi r

A = \frac{\theta}{360} \cdot \pi r^2