diff --git a/solutions/area_of_circle.py b/solutions/area_of_circle.py
new file mode 100644
index 000000000..c3562cfca
--- /dev/null
+++ b/solutions/area_of_circle.py
@@ -0,0 +1,47 @@
+"""
+A module for calculating the area of a circle.
+
+Module contents:
+    - area_of_circle: calculates the area of a circle given its radius.
+
+Created on 01 04 2025
+@author: Raghad
+"""
+
+import math
+
+
+# Define a function to calculate the area of a circle.
+def area_of_circle(radius: float) -> float:
+    """Calculate the area of a circle given its radius.
+
+    Parameters:
+        radius: float, the radius of the circle
+
+    Returns -> float: area of the circle
+
+    Raises:
+        ValueError: if the radius is negative
+
+    Examples:
+        >>> area_of_circle(5)
+        78.53981633974483
+        >>> area_of_circle(0)
+        0.0
+        >>> area_of_circle(3.5)
+        38.48451000647496
+    """
+    # Raise an error if the radius is negative.
+    if radius < 0:
+        raise ValueError("Radius cannot be negative")
+
+    # Calculate and return the area using the formula: area = π * r^2
+    return math.pi * radius**2
+
+
+# Entry point for script execution
+if __name__ == "__main__":
+    # Example usage: Calculate the area of a circle with a radius of 5.
+    radius = 5
+    area = area_of_circle(radius)
+    print("Area of the circle:", area)
diff --git a/solutions/remove_duplicates.py b/solutions/remove_duplicates.py
index 3b72fd373..8f3d46346 100644
--- a/solutions/remove_duplicates.py
+++ b/solutions/remove_duplicates.py
@@ -32,9 +32,9 @@ def remove_duplicates(nums: list) -> list:
     ['Heba', 'Noor']
     """
     assert isinstance(nums, list), "The input should be a list"
-    result = []  # List to store the result without duplicates
+    result = []  # List to store the result without duplicates.
 
     for num in nums:
         if num not in result:
-            result.append(num)  # Add the number to the result list
+            result.append(num)  # Add the number to the result list.
     return result
diff --git a/solutions/tests/test_area_of_circle.py b/solutions/tests/test_area_of_circle.py
new file mode 100644
index 000000000..82d575aae
--- /dev/null
+++ b/solutions/tests/test_area_of_circle.py
@@ -0,0 +1,38 @@
+import unittest
+from solutions.area_of_circle import area_of_circle
+
+
+class TestCircleArea(unittest.TestCase):
+    """Unit tests for the area_of_circle function."""
+
+    def test_positive_radius(self):
+        """Test the function with positive radius values."""
+        self.assertAlmostEqual(area_of_circle(5), 78.53981633974483)
+        self.assertAlmostEqual(area_of_circle(10), 314.1592653589793)
+
+    def test_zero_radius(self):
+        """Test the function with a zero radius."""
+        self.assertEqual(area_of_circle(0), 0.0)
+
+    def test_large_radius(self):
+        """Test the function with a very large radius."""
+        self.assertAlmostEqual(area_of_circle(1000), 3141592.653589793)
+
+    def test_negative_radius(self):
+        """Test the function with a negative radius."""
+        with self.assertRaises(ValueError) as context:
+            area_of_circle(-5)
+        self.assertEqual(str(context.exception), "Radius cannot be negative")
+
+    def test_invalid_type(self):
+        """Test the function with an invalid type for radius."""
+        with self.assertRaises(TypeError):
+            area_of_circle("string")
+        with self.assertRaises(TypeError):
+            area_of_circle([1, 2, 3])
+        with self.assertRaises(TypeError):
+            area_of_circle(None)
+
+
+if __name__ == "__main__":
+    unittest.main()
diff --git a/solutions/tests/test_remove_duplicates.py b/solutions/tests/test_remove_duplicates.py
index 33bcd99e4..9416ab8b2 100644
--- a/solutions/tests/test_remove_duplicates.py
+++ b/solutions/tests/test_remove_duplicates.py
@@ -1,7 +1,7 @@
 #!/usr/bin/env python3
 # -*- coding: utf-8 -*-
 """
-Test module for remove_duplicates function.
+Test module for remove_duplicates function
 
 Created on 2024-12-30
 Author: Heba Shaheen
@@ -17,17 +17,17 @@ class TestRemoveDuplicates(unittest.TestCase):
 
     # Standard test cases
     def test_numbers_list(self):
-        """It should remove duplicates numbers"""
+        """It should remove duplicates numbers. give [1, 2, 3, 4]"""
         self.assertEqual(remove_duplicates([1, 2, 3, 2, 3, 4]), [1, 2, 3, 4])
 
     def test_letters_list(self):
-        """It should remove duplicates letters"""
+        """It should remove duplicates letters. give ["a", "v", "e", "q"]"""
         self.assertEqual(
             remove_duplicates(["a", "v", "e", "e", "q"]), ["a", "v", "e", "q"]
         )
 
     def test_mix_list(self):
-        """It should remove duplicates items"""
+        """It should remove duplicates items. give [1, 2, 3, "e", 5, "a"]"""
         self.assertEqual(
             remove_duplicates([1, 2, 3, "e", 2, 1, "e", 5, "a"]), [1, 2, 3, "e", 5, "a"]
         )