Answer:
x=14
Explanation:
Since the triangles are similar, you first line up the sides. Then, because the 16 and the 24 line up together, you divide them to find out how much bigger the first triangle is, which is 3/2 or 1.5. After that, you can see that the 21 and the x are on the same side, so you would divide 21 by 1.5 or 3/2 to get x. 21รท1.5=14.
x=14