Added volume of a pyramid frustum

Added a function calculating volume of a pyramid frustum, V=(S1+S2+sqrt(S1*S2))*h/3

Author: kvadrik

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

@@ -102,4 +102,15 @@ public static double volumePyramid(double baseArea, double height) {
     public static double volumeFrustumOfCone(double r1, double r2, double height) {
         return (Math.PI * height / 3) * (r1 * r1 + r2 * r2 + r1 * r2);
     }
+
+    /**
+     * Calculate the volume of a frustum of a pyramid.
+     *
+     * @param upperBaseArea area of the upper base
+     * @param lowerBaseArea area of the lower base
+     * @param height height of the frustum
+     * @return volume of the frustum
+     */    
+    public static double volumeFrustumOfPyramid(double upperBaseArea, double lowerBaseArea, double height) {
+        return (upperBaseArea + lowerBaseArea + Math.sqrt(upperBaseArea * lowerBaseArea)) * height / 3;
 }