Question

Lesson 10 transformation rotation quick check

Answers

GPT-4o mini
Certainly! Here’s a quick check covering key concepts related to transformations, specifically focusing on rotation.

### Quick Check: Transformation - Rotation

1. **Definition of Rotation**:
- What is a rotation in geometric transformations?

2. **Center of Rotation**:
- Identify the center of rotation in a geometric figure. If a shape is rotated 90° around the origin, what remains unchanged?

3. **Angle of Rotation**:
- If a triangle with vertices A(1, 2), B(3, 2), and C(2, 4) is rotated 90° counterclockwise around the origin, what are the new coordinates of the vertices A', B', and C'?

4. **Counterclockwise vs. Clockwise**:
- Describe the difference between a counterclockwise rotation and a clockwise rotation.

5. **Matrix Representation**:
- Write the rotation matrix for a 180° rotation around the origin.

6. **Effects of Rotation**:
- How does rotation affect the size and shape of a geometric figure?

7. **Real-world Application**:
- Provide an example where rotation is used in real-life situations (e.g., in machinery or design).

8. **Finding the Angle**:
- If a point P(3, 4) is rotated to point P'(-4, 3) around the origin, what is the angle of rotation?

### Answers (for self-check):

1. A rotation is a transformation that turns a figure around a fixed point, called the center of rotation, by a specific angle in a specified direction.

2. The center of rotation is the point around which the shape is rotated. A shape rotated around the origin retains its location relative to the origin.

3. After applying a 90° counterclockwise rotation to the triangle's vertices:
- A'( -2, 1),
- B' ( -2, 3),
- C' ( -4, 2).

4. A counterclockwise rotation turns the figure in the opposite direction of a clock's hands, while a clockwise rotation turns it in the same direction as a clock's hands.

5. The rotation matrix for a 180° rotation is:
\[
R(180°) = \begin{bmatrix}
-1 & 0 \\
0 & -1
\end{bmatrix}
\]

6. Rotation does not affect the size or shape of a geometric figure; it only changes its orientation.

7. An example of rotation in real-life is the motion of the blades of a helicopter, which rotate around a fixed point.

8. To find the angle of rotation, observe the coordinates - a transformation from P(3, 4) to P'(-4, 3) involves a 90° counterclockwise rotation.

Feel free to modify or expand on any of these points as needed for your lesson!