geometry · Year 5 · AC9M5SP03
Translate, reflect and rotate
A transformation moves a shape. To find where a corner goes, follow that one corner. Translation slides the shape: add for right and up, subtract for left and down. Reflection flips it in a mirror line: count how far the corner is from the line, then go the same distance on the other side. Rotation turns it about a centre point P: note how far the corner is from P across and up, then turn those moves. For a quarter turn clockwise, 'right' becomes 'down' and 'up' becomes 'right'. For a half turn, both moves reverse. The image of A is written A′.
Sample questions
Triangle ABC is translated 2 units up. What are the coordinates of A′, the image of A?
- A is at (7, 4).
- 2 units up changes the up number: 4 + 2 = 6.
- A′ is at (7, 6).
Answer: (7, 6)
Triangle ABC is translated 3 units left. What are the coordinates of B′, the image of B?
- B is at (3, 10).
- 3 units left changes the across number: 3 − 3 = 0.
- B′ is at (0, 10).
Answer: (0, 10)
Triangle ABC is translated 5 units right. What are the coordinates of A′, the image of A?
- A is at (5, 3).
- 5 units right changes the across number: 5 + 5 = 10.
- A′ is at (10, 3).
Answer: (10, 3)