This question was uploaded on 12/01/22 on social media accounts.
Solution:
There are two similar triangles with the sides ratio of 3:1,
Due to semicircle, both are right angled triangle,
\[\Rightarrow \color{#ff6700}{3^2}+\color{#22bc22}{4^2}=\color{blue}{x^2}\]
\[\Rightarrow \color{blue}{x=5}\]
\[\Rightarrow \color{blue}{Blue}=\color{red}{Red}=5\]
