ABC is a right angled triangle with ∠ABC=90∘, the centre of the circle passing through A,B,C lies on _______.
AC
ABC is a triangle, so points A, B, C are non-collinear. Therefore a circle can be drawn passing through these three points. Now assume the center is on AB.
We know that angle subtended by a chord at the center is twice the angle subtended by it at any point on the circle.
The angle subtended by AB at the center is 180∘ since center lies on AB.
Therefore ∠ACB =90∘ which is not possible since sum of internal angles in a triangle is 180∘ and it is already given that ∠ABC=90∘.
So center cannot be on AB.
Similarly, you can prove that center does not lie on BC.
If we assume center lies on AC, then ∠ABC should be 90∘ which is given.
Therefore center lies on AC.