Question

HURRY! Point H is the circumcenter of triangle JKL. Which must be true?

Answer 1

A circumcentre is the centre of the circumcircle.  
The circumcircle of a triangle is the circle that passes through all three vertices.

Since all radii of a given circle are equal, we see that all the distances from H (circumcentre) to the vertices of the triangle are equal, namely
JH=KH=LH
Only one of the above answer choices is true.