F.4 Maths:Quadratic equation (b)(ii) AND(iii) AND (c)?

B(ii)
AD=BD --->angle ABD=angle BAC=36
angle ABC=(180-36)/2=72 ---> angle CBD=72-36=36
triangle ABC is similar to triangle BCD (AA)
(iii)
AB/BC=BC/CD

(C)
(i)AB/2=2/x --->AB=4/x

(ii)
4/x=x+2
x^2+2x-4=0
(iii)
x=-1+√5