Answer:
19.8 and 8/(sin(theta))+ 6/(cos(theta))
Explanation:
If you make a table you can see that L_1 + L_2 gets larger as you increase theta prom pi/2 and decrease theta from pi/2. This means that pi/2 is the theta that will yield the smallest length for the ladder. Plugging this into L_1 + L_2 you get 19.8 (rounded to the nearest hundred)
C = 8/(sin(theta))+ 6/(cos(theta))