Idea 6of 15Builds onFlip across a flat line
Fold to check a flip
How can you tell a real flip from a copy that was only slid?
Today you'll discover
- what a slid copy gets wrong
- where a real flip's corners go
- the fold test
Think firstIs the blue triangle a flip of the white one?
Is the blue triangle the white one flipped across the line?
Decide first, then press Next. Look at which way each triangle points.
Squared paper with a thick vertical line. Left of it, a white triangle; right of it, a blue copy pointing the same way. Dashed counts run from the white corners to the line and the same distance past it, landing on three green corners that join into the real flip, which faces the other way from the blue copy.
See the whole ideathe big idea and the key word, in one place
The big idea
A flip faces the opposite way; fold along the line and the two shapes match exactly.
Easy to get wrongA copy on the far side of the line is not always a flip. Count each corner to the line to be sure.
For exampleWrite the letter F and flip it across an up-and-down line: it faces left. That backwards F is its mirror image.
Key word
- orientation
- which way a shape faces
Ready to use it?
- Decide whether a copy is a flip or a slide.
- Check a flip by counting each corner to the line.