Trigeo

From the given conditions we get $\dfrac{(1-\cos Φ) ^2}{4}+\dfrac{\sin^2 Φ}{4(1-\cos Φ) ^2}=1\implies 4\sin^6\left (\dfrac{Φ}{2}\right ) -5\sin^2 \left (\dfrac{Φ}{2}\right) +1=0\implies \sin^2 \left (\dfrac{Φ}{2}\right) =0.20711\implies Φ\approx \boxed {54.141887\degree}$ .