MATHS 難題

If a circle is drawn to pass through the vertices of a triangle, what is the centre of the circle called?
A.Incentre of the triangle
B.Centroid of the triangle
C.Orthocentre of the triangle
D.Circumcentre of the triangle
答案是D
注
重心 Centroid = 三角形三條中線的相交點 ( Intersection of 3 Medians of a Triangle )
垂心 Orthocentre = 三角形三條高的相交點 ( Intersection of 3 Altitudes of a Triangle )
外心 Circumcentre = 三角形三邊的垂直平分線的相交點 ( Intersection of 3 Perpendicular Bisectors of the 3 sides of a Triangle )，亦是外接圓的圓心 ( Centre of Circumscribed Circle )
內心 Incentre = 三角形三條角平分線的相交點 ( Intersection of 3 Angle Bisectors of a Triangle )，亦是內接圓的圓心 ( Centre of Inscribed Circle )