Given:
To prove the similarity.
Two triangles similarity condition:
If two triangles are similar then the corresponding sides are proportional.
[tex]\Delta\text{OKJ Similar to }\Delta ONM[/tex][tex]\begin{gathered} \frac{OK}{ON}=\frac{OJ}{OM}=\frac{KJ}{NM} \\ \frac{3}{3+1}=\frac{30}{30+10} \\ \frac{3}{4}=\frac{30}{40} \\ \frac{3}{4}=\frac{3}{4} \end{gathered}[/tex]From the given values the corresponding sides are proves as propotional.
[tex]\Delta\text{OKJ Similar to }\Delta ONM[/tex]