| Exam Board | OCR |
|---|---|
| Module | C1 (Core Mathematics 1) |
| Year | 2008 |
| Session | January |
| Marks | 3 |
| Paper | Download PDF ↗ |
| Mark scheme | Download PDF ↗ |
| Topic | Circles |
| Type | Circle equation from centre and radius |
| Difficulty | Easy -1.3 Part (i) is direct recall of the standard circle equation formula requiring no working. Part (ii) involves completing the square to convert to centre-radius form, which is a routine C1 technique with straightforward arithmetic. Both parts are mechanical applications of standard methods with no problem-solving element. |
| Spec | 1.03d Circles: equation (x-a)^2+(y-b)^2=r^21.03e Complete the square: find centre and radius of circle |
2 (i) Write down the equation of the circle with centre $( 0,0 )$ and radius 7 .\\
(ii) A circle with centre $( 3,5 )$ has equation $x ^ { 2 } + y ^ { 2 } - 6 x - 10 y - 30 = 0$. Find the radius of the circle.
\hfill \mbox{\textit{OCR C1 2008 Q2 [3]}}