Shape Area Calculator in Java: Explanation & Practice

Problem summary

Create Shape hierarchy with Rectangle, Triangle, Circle. Each implements area().

Starter code

// Abstract Shape with abstract area()
// Rectangle: width * height
// Triangle: 0.5 * base * height
// Circle: PI * r * r

public class Main {
    public static void main(String[] args) {
        // Test case 1: Rectangle 4x5
        // Print: Area: <result>
    }
}

Expected output and test cases

• Rectangle 4x5

  Area: 20.0

• Triangle base 3, height 4

  Area: 6.0

• Circle radius 3

  Area: 28.27

Hints

1. Each shape stores its own dimensions
2. Override area() in each subclass
3. Use Math.PI for circle

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