How to change 78/5 into a mixed number​

Ineed if you could explain and give me the answer you! this needs done

Atriangle has a side lengths of 18cm, 80 cm and 81cm. classify it as acute obtuse or right?

There is an entrance to the computer room at point e which lies on ab and is 5 feet from point a. plot point e on the coordinate plane. find the distance from the entrance at point e to the printer at point e