19^2 = 361
7^2 = 49
361 - 49 = 312
Square root of 312 = 17.66
B) 17.7
The answer is 51/40=1 and 11/40
You do C = πd which it would be 69.08
Since s and t are complimentary, that means ∠s + ∠t = 90
From the picture, we also know that ∠t + ∠LGM = 90
Set them equal to each other:
∠s + ∠t = ∠t + ∠LGM, solve:
∠s = ∠LGM
Now using the fact that tangent = opposite/adjacent:
tan (∠s) = 
tan (∠s) = 
Set them equal to each other to get:
= 
Solve:

Part B:
Using tan (∠s) = 
We get:
meters
Hope that helps!