Unit 10: Circles || Quiz

What is the area formula for a circle?

A = πr²

What is the circumference formula for a circle?

C = 2πr

Circle

The set of all points in a plane that are equidistant from a fixed point of the plane called the center of the circle

Radius

A segment from the center of the circle to any point of the dircle

Central angle of a circle

An angle who's vertex is the center of the circle

Arc of a circle

The part of the circle between two points on the circle

Intercepted arc

An arc of a circle if each endpoint of the arc is a different ray of the angle and the other points of the arc and in the interior of the angle

Degree measure of an arc is equal to…

The measure of the central angle that intercepts the arc

Arc length

Measure of the distance along the arc

‘s’ is the symbol for

Arc length

Theta (kinda looks like this ∅) stands for:

The measure of a central angle

The formula for finding arc length is

s/2πr = ∅/360

Chord of a circle

A line segment whose endpoints are points of the circle

Diameter (chord wise)

A chord that has the center of the circle as one of its points

In a circle or congruent circles, two chords are congruent if…

And only if their central angles are congruent

A polygon is inscribed in a circle, and the circle is circumscribed about the polygon, if…

All of the verteces of the polygon are points of a circle

Inscribed angle of a circle

An angle whose vertex is on the circle and whose sides contain chords of the circle

The measure of an inscribed angle of a circle is equal to ___ of the measure of its intercepted arc

1/2

An angle inscribed in a semicircle is a ___ angle

Right - 90°

If two inscribed angles of a circle intercept the same arc, the angles are..

Congruent

If a line is drawn alongside a circle, it could intersect the circle ___ times

0, 1, or 2

Tangent to a circle:

A line in the plane of a circle, intersects at one and only one point

Secant of a circle

A line that intersects the circle at one point

At a given point on a circle, ___ line can be drawn that is tangent to the circle

1 and only 1

A line is tangent to a circle if and only if it is ___ to a radius at its point of ___ in the circle

Perpendicular, intersection