1what is a central angle?
An anhole whose vertex is at the ceneter of the circle and whose sides are radii that intersect the circle
2what is an inscribed angle?
an angle with its vertex on the circle and whose sides are chords of the circle
3what is special relationship between an inscribed angle and a centeral angle?
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.
4What is a radius?
a line from the center of the circle to any point on the circ;e
5what is a diameter of a circle?
a line that passes through the center and connects two points on the cirlce (twice the radius)
6What is a chord of a circle?
a line segment that connects two points on the circle, but does not need to go through the center.
7tangent
a line that touches the circle at exactly one point and does not cross into the circle
8What does the tangent line form with the circle?
the tangent line forms a right anlge (90 degrees) with the radius at the point of tangency. this
9how do you find the slope of a line tangent to a circle?
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
10 what is the equation of the circle?
(x - h)^2 + (y - k)^2 = r^2
11how do you find the center of the circle using the equation of the circle?
(h,k)
12how do you find the arc length of a angle in a circle
arc,length = \frac{\theta}{360} \cdot 2\pi r
13how do you find the area of an arc sector?
A = \frac{\theta}{360} \cdot \pi r^2