Suppose that triangle ABC is a right triangle; therefore, we can use the following trigonometric identities,
Then, in our case,
In a diagram,
Comparing the ratio of the corresponding sides of triangles ABC and RST
The ratio between corresponding sides is not constant; thus, triangle RTS is not similar to ABC.
On the other hand, as for triangle KJI
The ratio is constant; therefore, the answer is triangle JKI