1) I have to calculate the area of a kite $$ABCD$$ with $$AB-CD=(\sqrt {2}+1)(\sqrt{3}+1)$$ and $$11 \angle A= \angle C.$$
2) A second question is that if $$2 AB^2+AC^2+2 AD^2=4 BD^2$$ then there is $$ \angle A= 4\angle C.$$
My attempt: I think there is $$\angle A+\angle B+ \angle C +\angle D=2\pi$$ and $$AB=BC, CD=DA$$ and $$E=\frac{pq}{2}$$ for the area, but i have not any formulas for angles