Answer: x = 4
Explanation:
The attached photo shows a clearer illustration of the given triangle.
Looking at the photo, assuming ∆BCD is a right angle triangle. To determine BC, we would apply Pythagoras theorem which is expressed as
Hypotenuse² = opposite side² + adjacent side²
BC² = 9² + 6²
BC² = 81 + 36 = 117
BC = √117
To determine θ, we would apply the tangent trigonometric ratio.
Tan θ opposite side/adjacent side
Tan θ = 6/9 = 0.6667
θ = 33.6914
Considering ∆ABC,
Hypotenuse = x + 9
Adjacent = √117
Cos θ = adjacent side/ hypotenuse
Cos 33.6914 = √117/(x + 9)
Cross multiplying, it becomes
0.8320 = √117/(x + 9)
x + 9 = √117/0.8320
x + 9 = 13
x = 13 - 9 = 4