Programming C#

OOP Shape

Shape Area Perimeter
Rectangle a * b (a + b) / 2
Square a2 4 * a
Ellipse r1 * r2 * ℼ (r1 + r2) * ℼ
Circle r2 * ℼ 2 * r * ℼ
Triangle

$$\sqrt{p * (p - a) * (p - b) * (p - c)}$$

$$p = \frac{a + b + c}{2}$$

 a + b + c