Question

Fold a corner of a sheet of paper and then cut along the fold to get a right triangle. Let the right angle be $\angle C$. Fold each of the other two vertices so that they coincide with point. What result of this section does this illustrate?

Short answer

The result of this section illustrates that $CD=DX$.

Step-by-step solution

Step 1. Fold the sheet

Fold D onto BC so that the crease passes through C and unfold.

Step 2. Make the second fold

Fold A onto AD so that the crease passes through X as shown.

Step 3. Get the complete square.

Make the final fold to complete the square.

Above result shows that, $\angle DCX=45°$, right angles $\Delta CDX$has equal base angles.

Therefore, $CD=DX$, as required.