Please help me solve these questions for my physics assignment. Give full solutions and explanations please.

4 Tomorrow our sun is going to collapse and become a black hole. How far away from it's centre would the event horizon be? What orbital velocity would a probe need at this radius? b) Sagittarius A" ( the black hole at our galactic centre ) has a mass of 4 million Mo ( solar masses). Where is its event horizon located? what orbital velocity would a probe need here? 15