It is apparent that ketal and ketone share the same first three letters

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It is apparent that ketal and ketone share the same first three letters. That makes it easier to remember that:

1)acetals form from aldehydes

2)ketals form from ketones

That implies that:

3)cyclic hemiacetals form from cyclization of aldehydes

4)cyclic hemiketals form from cyclization of ketones

Let's take a look at how a cyclic hemiacetal forms.

I drew the less obvious arrows, but I'll leave the proton transfers for you to practice. The formation of a cyclic hemiketal is nearly identical; simply replace the explicit hydrogen with a methyl group.