| Exam Board | Edexcel |
|---|---|
| Module | C2 (Core Mathematics 2) |
| Marks | 4 |
| Paper | Download PDF ↗ |
| Mark scheme | Download PDF ↗ |
| Topic | Circles |
| Type | Find centre and radius from equation |
| Difficulty | Easy -1.2 This is a straightforward completing-the-square exercise to find circle centre and radius from general form. It requires only routine algebraic manipulation with no problem-solving or conceptual insight—significantly easier than average A-level questions which typically involve multi-step reasoning or application of techniques. |
| Spec | 1.03d Circles: equation (x-a)^2+(y-b)^2=r^21.03e Complete the square: find centre and radius of circle |
A circle $C$ has equation
$$x^2 + y^2 - 10x + 6y - 15 = 0.$$
\begin{enumerate}[label=(\alph*)]
\item Find the coordinates of the centre of $C$. [2]
\item Find the radius of $C$. [2]
\end{enumerate}
\hfill \mbox{\textit{Edexcel C2 Q1 [4]}}