A geometry problem by Shòvon saha

The distance of the point from the $y$ -axis is $|a|$

The distance of the point from the point $7,2$ is $\sqrt{(a-7)^2+(5-2)^2}$

Setting them equal

$\begin{aligned} &|a|=\sqrt{(a-7)^2+(5-2)^2}\\ \iff &|a|=\sqrt{a^2-14a+58}\\ \iff & a^2=a^2-14a+58\\ \iff &14a=58 \iff a=\dfrac{29}{7}≈\boxed{4.14} \end{aligned}$