Here,
cos(x) = sin(35)
cos(x) = cos(90-55)
cos(x) = cos(55)
x = 55
All you do is measure it with a ruler and for every 1 cm you get multiply it by 8.5ft.
so for example if you got 6cm then you would multiply it by 8.5ft and your answer would be 51ft.
The calculations for 2, 4, 8 year can be derived as follows,
For simple interest:
S.I =
P= principle
T= Time
R= Rate
For 2 year;
S.I = = $224
Amount = $2224
For 4 year;
S.I = = $448
Amount = $2448
For 8 year;
S.I = = $896
Amount = $2896