For each of the problems, twice the angle formed by the chords is equal to half the sum of the angles of the arcs.
So, for the first problem, we have

, so

.
For the second,

, so

.
For the last problem,

, so

.
Feel free to comment below if you have any questions!
Answer: r= 25/3
Step-by-step explanation:
r-4(r+6)=-49 distribute the 4
r-4r-24=-49 combine like terms
-3r-24=-49 add 24 to both sides
-3r=-25 divide by -3
r= 25/3 answer
8/2 = 4
answer: it will take Carlos 4 hours to walk 8 miles
Your answer is alredy in order