Answer:
 33 degrees
Explanation:
Angles BFG + GFC = 90
5r +68 + 8r +113 =90
1
Collect like terms 
13r + 181 = 90
Subract 181 from both sides 
13r = 90-181 
13r = - 91
r = - 7
Now insert the value of r into BFG (5r +68) 
5r + 68 = 5(-7) +68
= -35 + 68 
=33 
Check your answer by inserting the value of r into 8r +113 
8r + 113 =8(-7) +113
-56+113= 57 
The two angles 33 and 57 must add up to 90, a rt angle