What kinds of star forms a red giant?

Answer 1

Our star , the SUN , which currently is a mid-sized yellow star, will form a Red Giant, when all the hydrogen in the Sun has fused into helium, and then into carbon.

When it is doing this it will expand to such as size that it will swallow up the four rocky inner planets ( Mercurty, Venus, Earth & Mars).

Answer 2

when Dwarf Stars run out of hydrogen they form Red Giant stars, then from that they become White dwarf stars when the outer layers shed, forming a planetary nebula.

when giant stars or supergiant stars run out of hydrogen they form red supergiant stars

Answer 3

A red giant is formed when a low- to medium-mass star expands and cools off near the end of its life cycle. Main sequence stars similar in mass to the sun will eventually evolve into red giants.