Circles Maths - Circles

In the given figure, $CD$ is the diameter of a circle with centre $O$ and $CD$ is perpendicular to chord $AB.$ If $AB = 12\ cm$ and $CE = 3\ cm,$ then radius of the circles is:

• A
  $6\ cm$
• B
  $9\ cm$
• ✓
  $7.5\ cm$
• D
  $8\ cm$

Answer: C.

• A
  $11.5\text{cm}$
• ✓
  $12\text{cm}$
• C
  $\sqrt{69}\text{cm}$
• D
  $23\text{cm}$

Answer: B.

In the given figure, $\text{AOB}$ is a diameter of a circle with centre $O$ such that $AB = 34\ cm$ and $CD$ is a chord of length $30\ cm$. Then the distance of $CD$ from $AB$ is:

• ✓
  $8\ cm$
• B
  $15\ cm$
• C
  $18\ cm$
• D
  $6\ cm$

Answer: A.

In the given figure $, \text{BOC}$ is a diameter of a circle with centre $O$. If $\angle\text{BCA}=30^\circ$ then $\angle\text{CDA}=?$ 

• A
  $30^\circ$
• B
  $45^\circ$
• ✓
  $60^\circ$
• D
  $50^\circ$

Answer: C.

• A
  $45^\circ$
• B
  $60^\circ$
• ✓
  $90^\circ$
• D
  $36^\circ$

Answer: C.