Where Schwarzschild equation is a generalization of Pythagorus's
equation in rt. triangle and yet still forms the basis for black holes
mathematics and physics.
Go to:
https://www.relativitycalculator.com...al_offers.html
But in particular, go to:
https://www.relativitycalculator.com...ack-holes.html
Check it out.
The Relativity Man
Relativity Physics and Science Calculator