Fix pyramid surface area validation messages

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

@@ -4,6 +4,7 @@
  * Find the area of various geometric shapes
  */
 public final class Area {
+
     private Area() {
     }
 
@@ -69,7 +70,7 @@ 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
@@ -78,16 +79,15 @@ public static double surfaceAreaSphere(final double radius) {
      */
     public static double surfaceAreaPyramid(final double sideLength, final double slantHeight) {
         if (sideLength <= 0) {
-            throw new IllegalArgumentException("");
+            throw new IllegalArgumentException("Must be a positive sideLength");
         }
         if (slantHeight <= 0) {
-            throw new IllegalArgumentException("slant height must be greater than 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.
      *