/**
 * 三角形（已知底与高）：面积 = 底 * 高 / 2
 */
public class Triangle extends Shape {

    private final double base;
    private final double height;

    public Triangle(double base, double height) {
        if (base <= 0 || height <= 0) {
            throw new IllegalArgumentException("底和高必须为正数");
        }
        this.base = base;
        this.height = height;
    }

    public double getBase() {
        return base;
    }

    public double getHeight() {
        return height;
    }

    @Override
    public double getArea() {
        return base * height / 2.0;
    }
}