Question 16
We have a paper pentagon $ABCDE$ such that
$$
AB = BC = 3 \text{ cm},\ CD = DE = 5 \text{ cm},\ EA = 4 \text{ cm};\ \angle ABC = 100^\circ,\ \angle CDE = 80^\circ.
$$
The pentagon must be divided into four triangles by means of three straight cuts, so that with the four triangles a rectangle is assembled, without gaps or overlaps. (The triangles may be rotated and/or turned over.)
$$
AB = BC = 3 \text{ cm},\ CD = DE = 5 \text{ cm},\ EA = 4 \text{ cm};\ \angle ABC = 100^\circ,\ \angle CDE = 80^\circ.
$$
The pentagon must be divided into four triangles by means of three straight cuts, so that with the four triangles a rectangle is assembled, without gaps or overlaps. (The triangles may be rotated and/or turned over.)