Question

if the first second and third term of a proportion are 12 28 and 39 respectively find the fourth term​

Answer 1

12: 28 :: 39 : x
=> 12/28 = 39/x
=> x = (39 × 28) ÷ 12
=> x = 91

Answer 2

12: 28 :: 39 : x

=>$\frac {12}{28} = \frac {39}{x}$

=>$x = \frac {(39 \times 28)}{12}$

=>$x \: = \: 91$