# Maths - Circles

> Source: https://ollybritton.com/notes/a-level/maths/topics/circles/ · Updated: 2021-02-05 · Tags: maths

Circles are like smooth squares.

## Flashcards
##### ![PHOTO CIRCLE TANGENT](circle-tangent.png) What's the gradient of the line passing through the centre??
$$
\frac{2-5}{3-2} = -\frac{3}{2}
$$

##### ![PHOTO CIRCLE TANGENT](circle-tangent.png) If the gradient of the line passing through the centre is $-\frac{3}{2}$, what is the gradient of the tangent??
$$
\frac{2}{3}
$$

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