An angle whose measure is less than that of a right angle is ____________.

Answer

To solve the question "An angle whose measure is less than that of a right angle is ____________," we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Definition of a Right Angle**:
- A right angle measures exactly 90 degrees.

2. **Identify Angles Less Than a Right Angle**:
- We need to find angles that measure less than 90 degrees.

3. **Recall the Types of Angles**:
- Angles can be classified based on their measures:
- Acute Angle: An angle that measures less than 90 degrees.
- Right Angle: An angle that measures exactly 90 degrees.
- Obtuse Angle: An angle that measures more than 90 degrees but less than 180 degrees.

4. **Conclude the Answer**:
- Since we are looking for an angle that is less than 90 degrees, the correct term is "Acute Angle."

### Final Answer:
An angle whose measure is less than that of a right angle is **Acute Angle**.

---