Answer:
EF is 7
Step-by-step explanation:
Key skills needed: Triangle Congruence
1) We need to find out The length of EF
2) To find this, let's use Congruence of Two Triangles
The triangles that we can prove congruent are Δ DFG and Δ DFE
3) Both share the side DF, so we have one side
Both have a right angle, < FDG is a right angle, and < FDE would also be right angle (you can prove this as ---> < FDE is supplementary to a right angle, and therefore it would also be a right angle)
Both share a congruent set of sides (GD and DE both are 5)
4) With the 3 things above we can say --> Δ DFG ≅ Δ DFE with SAS (side-angle-side)
5) This means that corresponding parts would be congruent.
FG ≅ EF. This means EF would be the same length as FG. Since FG is 7, then EF would be 7.
Hope you understood and have a nice day!! :D
