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

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 Check radius as the distance between the centre and the first point:
 .70862397833418</pre>
+=={{header|Julia}}==
+{{trans|Phix}}{{trans|F#}}
+<syntaxhighlight lang="julia">function findcircle(p1, p2, p3)
+    a, b = p1
+    c, d = p2
+    e, f = p3
+    a2b2 = a * a + b * b
+    ae = a - e
+    db = d - b
+    c2d2 = c * c + d * d
+    bf = b - f
+    ec = e - c
+    e2f2 = e * e + f * f
+    ca = c - a
+    fd = f - d
+    cx = 0.5 * (a2b2 * fd + c2d2 * bf + e2f2 * db) / (a * fd + c * bf + e * db)
+    cy = 0.5 * (a2b2 * ec + c2d2 * ae + e2f2 * ca) / (b * ec + d * ae + f * ca)
+    # any one of these should do / be nearly identical:
+    r123 = [(cx-a)^2 + (cy-b)^2, (cx-c)^2 + (cy-d)^2, (cx-e)^2 + (cy-f)^2]
+    @assert maximum(r123) - minimum(r123) < 1e-12
+    r = sqrt(sum(r123) / length(r123))
+    return (cx, cy), r
+end
+ctr, r = findcircle((22.83, 2.07), (14.39, 30.24), (33.65, 17.31))
+println("Centre = $ctr, radius = $r")
+</syntaxhighlight>{{out}}
+<pre>Centre = (18.978515660148815, 16.26541079771587), radius = 14.708623978334177</pre>
 =={{header|Phix}}==