Added surface area calculation for pyramid

Author: Leosly7663

src/main/java/com/thealgorithms/maths/Area.java

@@ -47,6 +47,24 @@ public static double surfaceAreaSphere(final double radius) {
         }
         return 4 * Math.PI * radius * radius;
     }
+    /**
+    * Calculate the surface area of a pyramid with a square base.
+    *
+    * @param sideLength side length of the square base
+    * @param slantHeight slant height of the pyramid
+    * @return surface area of the given pyramid
+    */
+    public static double surfaceAreaPyramid(final double sideLength, final double slantHeight) {
+    if (sideLength <= 0) {
+    throw new IllegalArgumentException("Must be a positive sideLength");
+    }
+    if (slantHeight <= 0) {
+    throw new IllegalArgumentException("Must be a positive slantHeight");
+    }
+    double baseArea = sideLength * sideLength;
+    double lateralSurfaceArea = 2 * sideLength * slantHeight;
+    return baseArea + lateralSurfaceArea;
+    }
 
     /**
      * Calculate the area of a rectangle.