Multiple hellos. It is 30 degrees.

Solution: (All angular measurements in degrees)

degrees

degrees

degrees

is an altitude and is a median and is on the line

If is an altitude, then and are .

Filling in relevant angles angles: ,

Area of

A median splits a triangle into two triangles equal in area.

Construct altitude . (dotted line in diagram, forgot to label O)

Two similar triangles are discovered, and (as and are parallel)

Calculate area of

(Because a median splits a triangle into two triangles equal in area.)

Hence,

Which means that and

Thus

Hence and are identical

Hence