The perimeter of a regular pentagon inscribed in a circle with radius 10 cm.

Here are the solutions for questions 103 and 104.

Question 103:
The perimeter of a regular pentagon inscribed in a circle with radius 10 cm.
A regular pentagon has 5 equal sides. When inscribed in a circle, we can divide it into 5 congruent isosceles triangles, with the center of the circle as their common vertex.
The central angle for each triangle is $\frac{360^\circ}{5} = 72^\circ$.
Let $s$ be the side length of the pentagon and $r$ be the radius of the circle.
Consider one of these isosceles triangles. We can draw an