15/13 * 13/15

is it:

13*13=169
15*15=225
=225/169

or

13*15=195
15*13=195
=195/195=1

2 answers

Your second answer is correct. When multiplying fractions, you multiply the numerators together and then the denominators.
I did it another way as well:
225/195* 169/195 = 38025/
195
38025/195=195

195/195=1