Idea 7of 15Builds onFold to check a flip
Flip on the coordinate grid
Can you find a flipped point's coordinates without drawing the flip?
Today you'll discover
- which number a flip changes
- how far past the line a point lands
- how to write the new corners
Think firstA triangle and an upright line at 8
The mirror line runs up and down through 8 across. A is at (5, 3). Where does A land?
Decide first, then press Next. Count from the point to the line, then the same past it.
A coordinate grid with a thick upright line at 8 across and a triangle to its left with corners A (5, 3), B (7, 6) and C (3, 8). A dashed count shows A is 3 squares from the line; it carries on 3 more squares to (11, 3). Then all three corners are flipped, to (11, 3), (9, 6) and (13, 8), and joined into a green triangle.
See the whole ideathe big idea and the key word, in one place
The big idea
Across an up-and-down line only the first number changes; across a side-to-side line, only the second.
Easy to get wrongDo not add the line's number to the point's. Count the distance from the point to the line first.
Key word
- reflected point
- where a point lands after a flip across a line
Ready to use it?
- Find the coordinates of a flipped point or shape.
- Say which coordinate a flip changes.