I'm not to clear on what this triangle is trying to say but if 18 is a side and 12 is a side let's use the Pythagorean theorem to solve for the other side 18²=a²+12² 324=a²+144 180=a² √180 = a 13.41 =a since x look about twice a x=2*13.41 x=26.8
you would use pythagorean theorem(a^2+b^2=c^2) but since you have a^2 (12) and c^2 (18) you would do. a^2-c^2=b^2. which is 12^2-18^2=-180. then you square root -180 and get 13.4 but since the x is the long line you would add 13.4+13.4 and get 26.8.
