What set of Ratios form a proportion? Medal and fan!

Question

xmissalycatx · Answer

Answer choices?

electronia · Answer

4/9 and 12/25 ,3/7 and 18/42, 5/11 and 20/45 last but not least 5/8,15/25

electronia · Answer

@xMissAlyCatx Help!

xmissalycatx · Answer

I have to go now :( Try to @ a qualified helper or a mod! :D

electronia · Answer

@Anaise Please help!

mathmale · Answer

Regarding the first set:  4/9 and 12/25

It may help (just a little) to re-write these fractions as $$\frac{ 4 }{9 },\frac{ 12 }{ 25 }$$

dayakar · Answer

if a/b, c/d are two ratios then
a/b = c/d 
a.b,c,d are in proportion

electronia · Answer

Oh, so its 3/7 18/42 as the aswer! Ok! That helped! Thank you!

mathmale · Answer

There are several ways in which you can check a pair of ratios to determine whether they form a proportion.  

One is to cross-multiply.  Does 4*25 equal 9*12?

Another is to reduce one or both of the given ratios.