First, students will be led to conjecture Pick's theorem.
Pick's Theorem by NRICH
Next, students will be led to prove Pick's theorem.
Proof of Pick's Theorem by NRICH
After that, students will see a visual proof of Pick's theorem.
Pick's theorem: The wrong, amazing proof by spacematt
Here's an interesting problem: Which regular polygons can you draw, such that all vertices are grid points?