Could someone Please help with this basic trig problem

when a ten ft tall flagpole casts a nine foot long shadow what is its angle of elevation from the sun?

You make the 10ft the vertical leg, and the 9ft the horizontal leg of the triangle. You can connect the two with the hypotenuse but you really don't have to.
This should set up something like this:

=> tan(theta)=10/9 --> tangent= opposite/adjacent
=> theta = tan^-1(10/9) = 48.01 degrees

|
|
|
|
| 10ft
|
|__________ø\
9ft

Tan ø = 10/9 (Opposite over adjacent)
ø = tan^(-1) (10/9)

The square root of (nine square + ten squared)

h = squareroot(181)

You cannot simplify the answer as 181 is prime.