Centre and radius of a circle passing through 3 points in a plane: Difference between revisions

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 {{draft task}}
 Write a function which returns the centre and radius of a circle passing through three point in a plane. Demonstrate the function using the points (22.83,2.07) (14.39,30.24) and (33.65,17.31)
+=={{header|C++}}==
+This follows the lines of the C++ code [https://www.geeksforgeeks.org/equation-of-circle-when-three-points-on-the-circle-are-given/ here].
+<syntaxhighlight lang="c++">#include <iostream>
+#include <math.h>
+using namespace std;
+void findCircle(float x1, float y1, float x2, float y2, float x3, float y3) {
+    float x12 = x1 - x2;
+    float x13 = x1 - x3;
+    float y12 = y1 - y2;
+    float y13 = y1 - y3;
+    float y31 = y3 - y1;
+    float y21 = y2 - y1;
+    float x31 = x3 - x1;
+    float x21 = x2 - x1;
+    float sx13 = pow(x1, 2) - pow(x3, 2);
+    float sy13 = pow(y1, 2) - pow(y3, 2);
+    float sx21 = pow(x2, 2) - pow(x1, 2);
+    float sy21 = pow(y2, 2) - pow(y1, 2);
+    float f = ((sx13) * (x12) + (sy13) * (x12) + (sx21) * (x13) + (sy21) * (x13))
+            / (2 * ((y31) * (x12) - (y21) * (x13)));
+    float g = ((sx13) * (y12) + (sy13) * (y12) + (sx21) * (y13) + (sy21) * (y13))
+            / (2 * ((x31) * (y12) - (x21) * (y13)));
+    float c = -pow(x1, 2) - pow(y1, 2) - 2 * g * x1 - 2 * f * y1;
+    float h = -g;
+    float k = -f;
+    float r = sqrt(h * h + k * k - c);
+    cout << "Centre is at (" << h << ", " << k << ")" << endl;
+    cout << "Radius is " << r;
+}
+int main() {
+    findCircle(22.83, 2.07, 14.39, 30.24, 33.65, 17.31);
+    return 0;
+}</syntaxhighlight>
 =={{header|F_Sharp|F#}}==