Va rog frumos sa ma ajutați ! Repede!

a. 4/5=12/15
4×15=5×12
60=60 (A)
b. 14/10=21/15
14×15=10×21
210=210 (A)
c. 12/2=30/5
12×5=2×30
60=60 (A)
d. 4/36=7/63
4×63=36×7
252=252 (A)