The document contains five mathematical problems related to circles and arcs. Here’s a brief outline of each problem:

1. Problem 1: Calculate the length of arc CD given that arc AB is 10 cm, with both having specified central angles (though details of angle for CD are missing in the upload).

2. Problem 2: Calculate the length of arc AB given that the central angle $\angle AMB$ and radius AM = 7 cm are provided.

3. Problem 3: With O as the center of a circle and $\angle AOC$ given:

   • (a) Find the reflex angle of $\angle AOC$.
   • (b) Determine the measure of $\angle ABC$.

4. Problem 4: Given a circle centered at O with a perpendicular line to CD:

   • (a) Identify the diameter.
   • (b) Name the chord.
   • (c) Identify the sector.
   • (d) Identify the apothem.

5. Problem 5: Calculate the area of the sector AMB from Problem 2, with radius AM = 7 cm.

Would you like help solving one of these problems or all of them?

Here are some follow-up questions for more details:

1. What is the central angle of arc CD in problem 1?
2. Do you need a formula recap for arc length?
3. Would you like a solution for the reflex angle in problem 3(a)?
4. Is there a specific element (e.g., apothem or chord) you'd like explained from problem 4?
5. Shall I guide you through finding the sector area in problem 5?

Tip: Arc length is calculated using the formula $L = r \theta$, where $L$ is the length, $r$ is the radius, and $\theta$ is the central angle in radians.