Update sphere.py with new feature

added surface area function (using formula 4pi * r^2

Co-Authored-By: EyerusalemAbebaw <[email protected]>

src/geometry/sphere.py

@@ -0,0 +1,21 @@
+from math import pi
+
+
+def calculate_surface_area(r):
+    """ 
+    Calculate the surface area of a sphere. 
+
+    This uses the standard mathematical calculation: 
+
+    $4\pi r ^2$
+
+    Parameters
+    ----------
+    r : float, the radius 
+
+    Returns
+    -------
+    float : the surface area of the sphere
+    """
+    surface_area = 4 * pi * r **2
+    return surface_area