Question

Solve the proportion: x/9 = 4/x

Answer 1

$\frac{x}{9}= \frac{4}{x} \\ x*x=9*4 \\ x^2=36 \\ x=б \sqrt{36} \\ x=б6$

Answer 2

x       4        
--  =  --  =  
9       x       

x^2 = 36
x = 6