TheAlgorithms · realDuYuanChao · Aug 16, 2020 · Aug 16, 2020 · Aug 16, 2020 · Aug 16, 2020
@@ -115,7 +115,8 @@
  * [AbsoluteMin](https://github.com/TheAlgorithms/Java/blob/master/Maths/AbsoluteMin.java)
  * [AbsoluteValue](https://github.com/TheAlgorithms/Java/blob/master/Maths/AbsoluteValue.java)
  * [AmicableNumber](https://github.com/TheAlgorithms/Java/blob/master/Maths/AmicableNumber.java)
-  * [CountDigit](https://github.com/TheAlgorithms/Java/blob/master/Maths/CountDigit.java)
+  * [Area](https://github.com/TheAlgorithms/Java/blob/master/Maths/Area.java)
+  * [Average](https://github.com/TheAlgorithms/Java/blob/master/Maths/Average.java)
  * [Factorial](https://github.com/TheAlgorithms/Java/blob/master/Maths/Factorial.java)
  * [FactorialRecursion](https://github.com/TheAlgorithms/Java/blob/master/Maths/FactorialRecursion.java)
  * [FibonacciNumber](https://github.com/TheAlgorithms/Java/blob/master/Maths/FibonacciNumber.java)

@@ -0,0 +1,119 @@
+package Maths;
+
+/**
+ * Find the area of various geometric shapes
+ */
+public class Area {
+    public static void main(String[] args) {
+        /* test cube */
+        assert surfaceAreaCube(1) == 6;
+
+        /* test sphere */
+        assert surfaceAreaSphere(5) == 314.1592653589793;
+        assert surfaceAreaSphere(1) == 12.566370614359172;
+
+        /* test rectangle */
+        assert surfaceAreaRectangle(10, 20) == 200;
+
+        /* test square */
+        assert surfaceAreaSquare(10) == 100;
+
+        /* test triangle */
+        assert surfaceAreaTriangle(10, 10) == 50;
+
+        /* test parallelogram */
+        assert surfaceAreaParallelogram(10, 20) == 200;
+
+        /* test trapezium */
+        assert surfaceAreaTrapezium(10, 20, 30) == 450;
+
+        /* test circle */
+        assert surfaceAreaCircle(20) == 1256.6370614359173;
+
+    }
+
+    /**
+     * Calculate the surface area of a cube.
+     *
+     * @param sideLength side length of cube
+     * @return surface area of given cube
+     */
+    public static double surfaceAreaCube(double sideLength) {
+        return 6 * sideLength * sideLength;
+    }
+
+    /**
+     * Calculate the surface area of a sphere.
+     *
+     * @param radius radius of sphere
+     * @return surface area of given sphere
+     */
+    public static double surfaceAreaSphere(double radius) {
+        return 4 * Math.PI * radius * radius;
+    }
+
+    /**
+     * Calculate the area of a rectangle
+     *
+     * @param length length of rectangle
+     * @param width  width of rectangle
+     * @return area of given rectangle
+     */
+    public static double surfaceAreaRectangle(double length, double width) {
+        return length * width;
+    }
+
+    /**
+     * Calculate the area of a square
+     *
+     * @param sideLength side length of square
+     * @return area of given square
+     */
+    public static double surfaceAreaSquare(double sideLength) {
+        return sideLength * sideLength;
+    }
+
+    /**
+     * Calculate the area of a triangle
+     *
+     * @param base   base of triangle
+     * @param height height of triangle
+     * @return area of given triangle
+     */
+    public static double surfaceAreaTriangle(double base, double height) {
+        return base * height / 2;
+    }
+
+    /**
+     * Calculate the area of a parallelogram
+     *
+     * @param base   base of parallelogram
+     * @param height height of parallelogram
+     * @return area of given parallelogram
+     */
+    public static double surfaceAreaParallelogram(double base, double height) {
+        return base * height;
+    }
+
+    /**
+     * Calculate the area of a trapezium
+     *
+     * @param base1  upper base of trapezium
+     * @param base2  bottom base of trapezium
+     * @param height height of trapezium
+     * @return area of given trapezium
+     */
+    public static double surfaceAreaTrapezium(double base1, double base2, double height) {
+        return (base1 + base2) * height / 2;
+    }
+
+    /**
+     * Calculate the area of a circle
+     *
+     * @param radius radius of circle
+     * @return area of given circle
+     */
+    public static double surfaceAreaCircle(double radius) {
+        return Math.PI * radius * radius;
+    }
+}
@@ -0,0 +1,26 @@
+package Maths;
+
+/**
+ * Calculate average of a list  of numbers
+ */
+public class Average {
+    public static void main(String[] args) {
+        assert average(new double[]{3, 6, 9, 12, 15, 18, 21}) == 12;
+        assert average(new double[]{5, 10, 15, 20, 25, 30, 35}) == 20;
+        assert average(new double[]{1, 2, 3, 4, 5, 6, 7, 8}) == 4.5;
+    }
+
+    /**
+     * Calculate average of a list  of numbers
+     *
+     * @param numbers array to store numbers
+     * @return mean of given numbers
+     */
+    public static double average(double[] numbers) {
+        double sum = 0;
+        for (double number : numbers) {
+            sum += number;
+        }
+        return sum / numbers.length;
+    }
+}