Circle Vocabulary
A line segment that connects two points on a circle
What is a chord?
This formula will allow you to find the area of a circular region
What is A = pi * r^2
The measure of an inscribed angle that intercepts an arc of 100 degrees
What is 50 degrees?
It is the approximate value of pi to the nearest hundredth.
What is 3.14?
"x, and x, and x root 2! Congruent sides, we've got 2!" is a catchy song referring to this special type of right triangle.
What is a 45-45-90?
The longest chord in any circle
What is a diameter?
This formula will allow you to find the distance around the outside of a circular region.
What is C = 2 * pi * r?
Inscribed angles subtended by a semicircle are always this type of "correct" angle.
What are right angles?
What is 2pi?
The formula 1/2 bc sin A is the "SAS"sy formula to help you find the area of this type of figure.
What is a triangle?
A line that intersects the circle at only one point
What is a tangent?
It is the center of the circle with this equation:
(x - 2)^2 + (y + 5)^2 = 64
What is (2, -5)?
To measure a positive angle, one must always move in "this" direction
What is counter-clockwise?
It is the EXACT area of a circle with a radius of 9 cm (in terms of pi).
What is 81pi square centimeters?
If you were to draw two different chords and bisect them, the two bisectors would intersect at this point.
What is the center?
A straight line that passes through two points on a circle
What is a secant?
It is the length of the diameter of the circle with this equation:
(x - 4)^2 + (y - 10)^2 = 36
What is 12 units?
It is the central angle measurement of a slice of pizza if the pie has been cut into 12 equal slices.
What is 30 degrees?
It is the EXACT area of the sector with a central angle of 90 degrees and a radius of 10 shown in the diagram.
What is 25pi?
It is the length of the short leg in a 30-60-90 triangle with a hypotenuse of 30.
What is 15?
An angle having its vertex on the circle and whose sides are chords of the circle
What is an inscribed angle?
The formula n/360 * pi * r^2 will allow you to find this portion of your circle.
What is a sector?
It is the measure of the angle shown in this diagram if the subtended arcs are 120 and 40 degrees.
What is 80 degrees?
It is the number of radians in a semicircle
It is the length of the radius in the diagram shown when the chord DE is bisected by segment AC
What is 5 units?