To complete the identity, we need these fundamental identities:



Thus, by identity 1 we have:

by identity :

recall the values :


,
so:

Putting all these together, we have:

which is equal to

, by identity 3
Answer: D
His shadow will most likely be 7 feet long
Answer:
see explanation
Step-by-step explanation:
look at the photo
here the length AB is the difference between 17 and -34.
i.e. AB=17-(-34)=17+34=51 units
RS + ST = RT
3x + 1 + 2x - 2 = 64
5x - 1 = 64
5x = 64 + 1
5x = 65
x = 65/5
x = 13 <==