Answer:
C. x=2.5, DC=7.5, EC=15
Step-by-step explanation:
since the triangles have congruent angles, the sides have a relationship too. Basically, the ratio between the triangle is 4:10 because those sides math up. So, that also means it is 2:5. Therefore, BC:EC=6:15. 15-12.5=2.5, so x=2.5.
Now you can just do 2.5+5=7.5 so DC=7.5
