Question

if an orthocenter lies inside of a triangle, then the triangle must be isosceles. obtuse. right. acute.

Explanation:

The orthocenter is the intersection of a triangle's altitudes. For an acute triangle, all altitudes lie inside the triangle, so their intersection (orthocenter) is inside. For obtuse triangles, the orthocenter is outside; for right triangles, it is at the right-angled vertex; isosceles triangles can be acute, right, or obtuse, so their orthocenter is not always inside.

Answer:

acute.