1. (10 points) Two neighbors ordered sectional fences for their plots. Ivan Ivanovich bought a fence of traditional shape, each section of which is a rectangle with sides 5 by 2. Petr Petrovich, on the other hand, took a fence with slanted sections in the form of parallelograms with sides 5 by 2. The number of sections ordered by the neighbors is the same. Compare the amount of paint that will be used to paint each of the fences, assuming the thickness of the applied paint layer is constant and the same for both fences.

a) Ivan Ivanovich and Petr Petrovich will use the same amount of paint.

b) Ivan Ivanovich will use more paint.

c) Petr Petrovich will use more paint.

2) It is impossible to compare the amount of paint required to paint the fences based on the available data.
Answer: b).

Solution: From the condition, it is clear that the sections of the fence of Pyotr Petrovich have the shape of a parallelogram, in which there are no right angles. This means that if $\alpha$ is any angle between the sides of this parallelogram, then $\sin \alpha < 1$. Therefore, the area of a section of Pyotr Petrovich's fence, which is $5 \cdot 2 \cdot \sin \alpha = 10 \cdot \sin \alpha$, is definitely less than the area of a section of Ivan Ivanovich's fence, which is $5 \cdot 2 = 10$. Accordingly, the total area of Ivan Ivanovich's fence is also larger, so he will use more paint.