cos θ = 0.5333
inverse cosine both sides of equation
cos⁻¹(cos θ) = cos⁻¹(0.5333)
on left side, cosine cancel out
on right side use calculator in radian mode
θ = 1.0083
for the ttriangle, assuming c is the hypotenuse
pythagoras
a² + b² = c²
b² = c² - a²
b = √(c² - a²)
b = √(9² - 2²)
b = 8.77
