Sandys suggestion is interesting. Im sure it works...
A more everyday advice along the same idea is to order the dogs to lay down, and let the first meeting be when they lay down: the cat smelling and searching off the dogs in its own pace.
Here too the extra effect is teaching the dogs the cat belongs to the group - and is high on the hierarchy ladder.
Let them see you (ie the dog owner!) are holding the cat and are friendly to him = he belongs to the group.
See to give the cat lotsa smells from the dog-owner!
ps: here it is essential the dog-owner presents the cat him being the unquestionable alpha. Unless you the cat-owner are firmly recognized as the female alpha of the group... In this case, you can share the introduction.
Dogs are very group-oriented: as soon they realise the cat belongs - they will accept him, even protect him if need be.
With a little luck - be also pals or even good friends.
If you are the least unsure: do it with one dog at a time, the other dog somewhere else...
Make sure the cat has somewhere to run off if need be: preferably high up. But if the dogs are big - down under works also fine...

As Sandy said: The family cat should be safe. But other cats arent necessary safe: they dont belong to the family-group...
Unless you actively train the dogs not to attack any cat at all. But this is a different story...
good luck!