Are 30, 40, 45, 60 in proportion?

The correct answer is Yes

30:40 = $\dfrac{30}{40}$ = $\dfrac{3}{4}$

45:60 = $\dfrac{45}{60}$ = $\dfrac{3}{4}$

∴ 30:40 = 45:60
Hence 30, 40, 45, 60 are in proportion