Ronda Rousey -- Shaq Is Right ... He Could Last 45 Secs with Me

She'd probably beat his ass in the end, but Ronda Rousey says she AGREES with Shaquille O'Neal -- that he could probably last 45 seconds in the Octagon before getting him to tap out.

Shaq made the prediction on "Inside the NBA" last week -- saying, "It's not a joke! I could last 45 seconds!"

So, when we saw Ronda at LAX this weekend -- we had to ask how she felt about the situation ... and she explains why Shaq is 100% correct.

BTW -- here's the tale of the tape:

Shaquille O'Neal:
Height -- 7'1"
Weight -- 325 lbs

Ronda Rousey
Height -- 5'7"
Weight -- 135 lbs

Bonus -- we also asked Rousey about the guy who tested a new "bulletproof cup" that some men could be wearing in MMA in the near future.

Here's that video, too ...