Answer: 83.
Step-by-step explanation:
We know that if two triangles are congruent then their corresponding parts are also congruent by CPCTC .
If Triangle RSV is congruent to triangle TVS, then their corresponding angles are also congruent .
[tex]\angle{V}=\angle{S}[/tex] [The third letter of each triangle name]
[tex](x-5)^{\circ}=78^{\circ}\\\\\Rightarrow\ x-5=78[/tex]
Add 5 on both the sides of the equation , we get
[tex]x=78+5=83[/tex]
Hence, the value of x = 83
