Question

What is the value of X?​

Answer 1

The value of X is 5 because the dimensions of the first triangle is x=5 and 15 so therefore the second triangle has to have the same dimensions according to X so that would be 15 and 6(X)=30. As a result, X=5

Answer 2

the assumption here is that both triangles are similar, if that's so, then we can use proportions to get the sides.

$\stackrel{\textit{assuming both triangles are similar}}{\cfrac{x}{10}=\cfrac{15}{6x}\implies \cfrac{x}{10}=\cfrac{5}{2x}}\implies 2x^2=50 \\\\\\ x^2=\cfrac{50}{2}\implies x^2=25\implies x=\sqrt{25}\implies \boxed{x=5}$