Answer:
(1,6)
Step-by-step explanation:
We are given that the vertices of triangle ABC are A at (1,2),B at (1,6) and C at (5,6).
We have to find the coordinates of the orthocenter.
Distance formula: 
Using distance formula


Hence, the triangle is a right triangle because it satisfied Pythagoras theorem

The orthocenter is the intersection of three altitudes of triangle .The orthocenter of right triangle is the vertex of triangle .
The vertex of triangle is at B.
Therefore, the ortho-center of triangle ABC is B(1,6).