```In the diagram below, rectangle OABC is enlarged into rectangle OA1B1C1 from centre O.


|OC|=5cm, |OA|=2cm and |AA1| = 1cm

Use the diagram to answer Questions 21 and 22```
Find the scale factor of the enlargement.

• A.1
• B.1.5
• C.2
• D.2.5