Question

Cine ma ajuta,va rog??urgenttt​

Answer 1

a)

$\it \left.\begin{aligned} \it CA\perp AB\ \ \ \ \ \\ \\ CA\perp AD\ \ \ \ \\ \\ AB\cap AD=\{A\}\end{aligned}\right\} \Rightarrow CA\perp (ABD) \Rightarrow CA\perp \alpha$

b) Cu teorema lui Pitagora ⇒ AD=9cm,  AB=16cm

$\it \mathcal{A}_{ABD}=\dfrac{AD\cdot AB\cdot sin60^o}{2}=\dfrac{9\cdot16\cdot\dfrac{\sqrt3}{2}}{2}=9\cdot4\sqrt3\ =36\sqrt3cm^2\\ \\ \\ \mathcal{A}_{ABD}=\dfrac{BD\cdot AE}{2} \Rightarrow 36\sqrt3=\dfrac{18\cdot AE}{2} \Rightarrow 36\sqrt3=9\cdot AE\bigg|_{:9} \Rightarrow AE=4\sqrt3cm$