Answer:
-1/9
Step-by-step explanation:
y2-y1
x2-x1
Answer:

Step-by-step explanation:
Because vertical angles are always equal, we want to solve
.
We can add 10 to both sides to get
.
We can subtract
from both sides to get
.
Lastly, we divide both sides by 20 to get
.
So,
and we're done!
The check is left as an exercise to the reader.
GH=JH
H1 = H2 (vertical angles)
FH=HI
so the triangles are congruent by SAS theorem
FGH=HIJ => FG=JI
good luck