The sides of a right angled triangle are in A.P then their ratio is.

Let c be the hypotnues $a^2+b^2=c^2$ a, b, c are in A. P

$\Rightarrow b=\frac{a+c}{2}\Rightarrow a^2+b^2=c^2\Rightarrow a^2+{\left(\frac{a+c}{2}\right)}^2=c^2$

$$\begin{gathered} \Rightarrow 5a^2+2ac-3c^2=0\Rightarrow c=\frac{5a}{3},b=\frac{4a}{3} \\ \Rightarrow a:b:c=3:4:5 \end{gathered}$$