Just a guess but 75 degrees?
Answer is (d) P, Q , R
Any triangle has 3 vertices , after which its name is justified
Answer:

Step-by-step explanation:

You can consider the triangle (as on in the picture) and apply to it composition of two transformations:
1. reflection about the line y=x to form ΔA'B'C' and translation 1 unit right and 5 units up to form ΔA''B''C'';
2. translation 1 unit right and 5 units up to form ΔA'B'C' and reflection about the line y=x to form ΔA''B''C''.
You can see that results are different.
On added picture blue colour responds to composition of transformations 1 and red colour to composition of transformations 2.
X = measure of each of the legs
"perimeter is 8 more than 2 times one of the legs" ---> P = 2x+8
P = 28 is the given perimeter
So,
P = 2x+8
28 = 2x+8
2x+8 = 28
2x = 20
x = 10
If x = 10, then the two legs add up to x+x = 10+10 = 20
Leaving P-20 = 28-20 = 8 inches left over for the base
You have the correct answer (choice D, 8 inches) though your steps are a bit confusing at some parts. Such as the part where you wrote 2x = 10 twice. I think I know what you were trying to say.