Added volume of a pyramid frustum

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

@@ -102,4 +102,16 @@ 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;
+    }
 }

src/test/java/com/thealgorithms/maths/VolumeTest.java

@@ -35,5 +35,8 @@ public void volume() {
 
         /* test frustum */
         assertEquals(359.188760060433, Volume.volumeFrustumOfCone(3, 5, 7));
+
+        /* test pyramid frustum */
+        assertEquals(140.0, Volume.volumeFrustumOfPyramid(6, 24, 10));
     }
 }