[ Cutting (other).]

Two people had two square cakes. Each made 2 straight cuts from edge to edge on their cake. As a result, one ended up with three pieces, and the other with four. How could this happen?
Note: Cuts can intersect.

## Solution

This could happen if in the first case the cuts did not intersect each other, while in the second case they did. For example, if in the first case the cuts were parallel to each other, and in the second case they were perpendicular.

## Answer

In the first case, the cuts were parallel to each other, and in the second case, they were perpendicular.

How many pieces can a round pancake be divided into with three straight cuts?

## Hint

Recall problem 11.

## Solution

If each of the three lines intersects the other two inside the pancake, it will result in 7 pieces (see Fig. 11.4). If any two of these lines are parallel or intersect outside the pancake, there will be fewer pieces.

## Answer

7 pieces.