Added Monte Carlo Pi Approximation (#201)

* Added Monte Carlo Pi Approximation

* Added comments

Maths/PiApproximationMonteCarlo.js

@@ -0,0 +1,25 @@
+// Wikipedia: https://en.wikipedia.org/wiki/Monte_Carlo_method
+// Video Explaination: https://www.youtube.com/watch?v=ELetCV_wX_c
+
+function piEstimation (iterations = 100000) {
+  let circleCounter = 0
+
+  for (let i = 0; i < iterations; i++) {
+    // generating random points and checking if it lies within a circle of radius 1
+    const x = Math.random()
+    const y = Math.random()
+    const radius = Math.sqrt(Math.pow(x, 2) + Math.pow(y, 2))
+
+    if (radius < 1) circleCounter += 1
+  }
+
+  // fomula for pi = (ratio of number inside circle and total iteration) x 4
+  const pi = (circleCounter / iterations) * 4
+  return pi
+}
+
+function main () {
+  console.log(piEstimation())
+}
+
+main()