Question

Please? I need help here

Answer 1

D

Explanation:

If pair of ratios does form a true proportion then:

`a:b=c:d\to(a)/(b)=(c)/(d)\to ad=bc`

`A)\\\\8:14=20:35\to(8)/(14)=(20)/(35)\\\\(8)(35)=(14)(25)\\\\280=280\qquad\bold{TRUE}\\\\b)\\\\(6)/(10)=(15)/(25)\\\\(6)(25)=(10)(15)\\\\150=150\qquad\bold{TRUE}`

`c)\\\\(9)/(5)=(27)/(15)\\\\(9)(15)=(5)(27)\\\\135=135\qquad\bold{TRUE}\\\\d)\\\\12:15=30:50\to(12)/(15)=(30)/(50)\\\\(12)(50)=(15)(30)\\\\600=450\qquad\bold{FALSE}`