The orthocentre o

Since , H is the orthocenter of the ΔABC

So, ADꞱBC , BEꞱAC and CFꞱAB

X, Y and Z are the midpoints of AH, BH and CH respectively

∴ XYZ is a triangle.

Hence, XZ||AC

So, ∠HOX=∠HEA=90°

Similarly, XY||AB

And ∠HPX=∠HFA=90°

And YZ||BC

So, ∠HQZ=∠HDC=90°

Hence, HO, HP and HQ are the altitudes of ∆XYZ

So, H is the orthocenter of ∆XYZ