Question

The first, second, and fourth terms of a proportion are $6,18$ and $75$ respectively. Find its third term.

Answer 1

Let the third term $=x$
$6:18::x:75$
$=18\times x=6\times 75$
$x=\frac{6\times 75}{18}=\frac{75}{3}=25$
The third term of proportion is $25$.