How do you draw a figure with a perimeter of 10 units?

An equilateral triangle with sides of 10/3 units, an isosceles triangle with 2 sides of a units and the third of 10-2a units (for any a<5), or several options for scalene triangles.

A square or rhombus with sides of 2.5 units, or a rectangle or parallelogram with sides of b and 5-b units etc

A regular pentagon with sides of 2 units.

And so on.