Answer:
The formula for the Schwarzchild radius of a black hole is given by
Rs = (M/Mo) x 3km.
Here Mo means the mass of the Sun.
For Earth, M/Mo = 0.000 003, that is, Earth has 0.000 003 x Mo.
Thus Earth's Schwarzchild radius is about 1 cm.
That means that if a giant squeezed Earth into a diameter less than 2cm,
it would be a black hole.