Ta có:
\(\dfrac{54}{90}=\dfrac{3}{5}\)
\(\dfrac{180}{288}=\dfrac{5}{8}\)
\(\dfrac{60}{135}=\dfrac{4}{9}\)
Có mẫu số chung là 360
\(\dfrac{3}{5}=\dfrac{3\cdot72}{5\cdot72}=\dfrac{216}{360}\)
\(\dfrac{5}{8}=\dfrac{5\cdot45}{8\cdot45}=\dfrac{225}{360}\)
\(\dfrac{4}{9}=\dfrac{4\cdot40}{9\cdot40}=\dfrac{160}{360}\)