Okey, sorry for the crap diagram!

Radius of the hemisphere is 6.

The question is:

Now the distance is:Find the horizontal distance from the center of mass of the hemisphere to the vertical through O.

3/8 x 6 = 2.25.

But then im stuck as to find the horizontal distance. If i assume the angle of the triangle formed is 60 degrees then i could do 2.25Cos60 which is 1.125...but i don't think its right to assume that.

The overall answer is 1.125.

Any help would be appreciated!

Thankyou .