Question

Determine if the following is in proportion.

$7x,9x,35,45$

Answer 1

If $a,b,c,d$are in proportion then,

$a\times d=b\times c$

So, here we have $7x,9x,35,45$

in which

$a=7x,b=9x,c=35,d=45$

now, $7x\times 45=315x$

and, $9x\times 35=315x$

Hence $a\times d=b\times c$

So, $7x,9x,35,45$ are in proportion.