Answer:
11.1 feet
Step-by-step explanation:
From the solution triangle attached, the required distance is represented as x ; the value of x can be obtained using trigonometry ;
Cosθ = opposite / Adjacent
Cos 20 = 10.5 / x
x * Cos 20 = 10.5
x = 10.5 / cos 20
x = 11.174 feets