Ta có:
\(a=36=2^2\cdot3^2\)
\(b=60=3\cdot2^2\cdot5\)
\(c=90=3^2\cdot2\cdot5\)
\(\Rightarrow\text{Ư}CLN\left(a,b,c\right)=\text{Ư}CLN\left(36;60;90\right)=3\cdot2=6\)
\(\Rightarrow BCNN\left(a,b,c\right)=BCNN\left(36,60,90\right)=3^2\cdot5\cdot2^2=180\)