Answer:
True
Explanation:
Consider triangle ABC inscribed in the circle with center at point O. Point O is a point of intersection of perpendicular bisectors of sides AC, AB and BC. According to the attached diagram, points E, F and G are midpoints of sides BC, AC and AB, respectively.
Then
Since segments OE, OF and OG are perpendicular bisectors of sides BC, AC and AB, then
- m∠OBE=m∠OCE=90°;
- m∠OCF=m∠OAF=90°;
- m∠OBG=m∠OAG=90°.
You get three pairs of congruent triangles:
- ΔOBE≅ΔOCE;
- ΔOCF≅ΔOAF;
- ΔOBG≅ΔOAG.
This gives you that

Each of these segments is a radius of the circumscribed circle about a triangle ABC, then the center of the circumscribed circle about a triangle is equidistant to the vertices of the inscribed triangle.