Which of the following statements is correct?

Options

A. A right angle is `1/2` of a revolution.
B. A straight angle is `1/4` of a revolution.
C. The measure of a reflex angle is greater than that of a straight angle.
D. The angle formed in one revolution is a reflex angle.

Explanation

To determine which of the statements is correct, we need to analyze each statement one by one based on our understanding of angles.

### Step-by-Step Solution:

1. **Understanding the First Statement:**
- The first statement claims that a right angle is half of a revolution.
- A revolution is defined as a complete circle, which measures 360 degrees.
- A right angle measures 90 degrees.
- To check if the statement is true, we can calculate:
\[ \text{Half of a revolution} = \frac{360 \text{ degrees}}{2} = 180 \text{ degrees} \]
- Since 90 degrees (right angle) is not equal to 180 degrees, the first statement is **incorrect**.

**Hint:** Remember that a right angle is 90 degrees, which is one-fourth of a revolution (360 degrees).

2. **Understanding the Second Statement:**
- The second statement claims that a straight angle is half of a revolution.
- A straight angle measures 180 degrees.
- We already calculated half of a revolution:
\[ \text{Half of a revolution} = 180 \text{ degrees} \]
- Since a straight angle is indeed 180 degrees, the second statement is **correct**.

**Hint:** A straight angle is exactly half of a full circle (360 degrees).

3. **Understanding the Third Statement:**
- The third statement claims that the measure of a reflex angle is always greater than a straight angle.
- A reflex angle is defined as an angle that is greater than 180 degrees but less than 360 degrees.
- Therefore, a reflex angle can be any angle from just above 180 degrees up to 360 degrees.
- Since reflex angles are always greater than 180 degrees (straight angle), this statement is also **correct**.

**Hint:** Reflex angles are always larger than straight angles.

4. **Understanding the Fourth Statement:**
- The fourth statement seems to claim something about angles formed in one revolution.
- A revolution is 360 degrees, but it does not specify any particular angle type.
- This statement is vague and cannot be considered correct without further clarification.

**Hint:** A revolution simply refers to a complete turn, which is always 360 degrees.

### Final Conclusion:
- The correct statements are:
- The second statement (a straight angle is half of a revolution) is **correct**.
- The third statement (the measure of a reflex angle is always greater than a straight angle) is also **correct**.
- The first statement is incorrect, and the fourth statement is vague.

Thus, the answer is that the second and third statements are correct.