# Trigonometry

Drag the black and white point around the circle to see its angle in both radians and degrees.

θ$* \frac{180}{\pi} =$0°

## Pythagoras

$a^2 + b^2 = c^2$

Move the sliders on the following graph to change the length of the sides in a right angled triangle. Click the "Show squares" option to display squares attached to each side of the triangle. The value of the hypotenuse is calculated based on Pythagoras' theorem and displayed below the graph.

a$^2 +$b$^2 =$ c$^2$
a$+$b$=$ c

## Unit Circle — Sine, Cosine and Tangent

Drag the black and white point around the circle and watch the sine, cosine and tangent change.

$sin($θ$) =$0
$cos($θ$) =$0
$tan($θ$) =$0

## Equation of a Circle

$(X - a)^2 + (Y - b)^2 = r^2$

The graph below displays a circle which can have its radius modified via the slider at the top, and its position changed by dragging the central point. The equation for this specific circle is displayed underneath the graph.

$(X -$a$)^2 + (Y -$b$)^2 =$r$^2$