Free Arc Length and Area of a Sector of a Circle Calculator - Calculates the arc length of a circle and the area of the sector of a circle

Free Chord Calculator - Solves for any of the 3 items in the Chord of a Circle equation, Chord Length (c), Radius (r), and center to chord midpoint (t).

Free Circle Equation Calculator - This calculates the standard equation of a circle and general equation of a circle from the following given items:
* A center (h,k) and a radius r
* A diameter A(a₁,a₂) and B(b₁,b₂)
This also allows you to enter a standard or general form equation so that the center (h,k) and radius r can be determined.

Free Circles Calculator - Calculates and solves for Radius, Diameter, Circumference, and Area of a Circle.

Free Circular Permutation Calculator - Calculates the following:
Number of ways to arrange n distinct items arranged on a circle

Free Describe Two-Dimensional Shapes Calculator - Calculates the following:
Given a description of a 2D shape, it will return the shape (Circle, rectangle, square, triangle, etc.)

Free Equilateral Triangle Calculator - Given a side (a), this calculates the following items of the equilateral triangle:
* Perimeter (P)
* Semi-Perimeter (s)
* Area (A)
* altitudes (h_a,h_b,h_c)
* medians (m_a,m_b,m_c)
* angle bisectors (t_a,t_b,t_c)
* Circumscribed Circle Radius (R)
* Inscribed Circle Radius (r)

Free Trig Measurement Calculator - Given an angle θ, this calculates the following measurements:
Sin(θ) = Sine
Cos(θ) = Cosine
Tan(θ) = Tangent
Csc(θ) = Cosecant
Sec(θ) = Secant
Cot(θ) = Cotangent
Arcsin(x) = θ = Arcsine
Arccos(x) = θ = Arccosine
Arctan(x) =θ = Arctangent
Also converts between Degrees and Radians and Gradians
Coterminal Angles as well as determine if it is acute, obtuse, or right angle. For acute angles, a cofunction will be determined. Also shows the trigonometry function unit circle

Free Unit Circle Calculator - Determines if coordinates for a unit circle are valid, or calculates a variable for unit circle coordinates

Free Venn Diagram (2 circles) Calculator - Given two circles A and B with an intersection piece of C, this will calculate all relevant probabilities of the Venn Diagram.

Free What is a Unit Circle Calculator - This lesson walks you through what a unit circle is and how to use it