# StudySquare

# Circles for Edexcel A-level Maths

This page covers the following topics:

1. Coordinate geometry of a circle

A circle that has a centre of coordinates (a, b) and a radius of length r has an equation of the form: (x − a)² + (y − b)² = r².

# 1

State the equation of a circle with centre (0, 5) and radius 8.

The circle has equation x² + (y − 5)² = 64.

# 2

State the equation of the given circle.

The circle has equation x² + (y + 4)² = 49.

# 3

State the equation of the given circle.

The circle has equation (x − 3)² + y² = 9.

# 4

A circle has equation x² + y² = 9. State the coordinates of the centre of the circle and the length of its radius.

The circle has centre (0, 0) and radius of length 3.

# 5

State the equation of the given circle.

The circle has equation (x − 2)² + (y − 5)² = 25.

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