Question

Dau coroana jur
E urgent pls

Answer 1

ABCDA'B'C'D' CUB
M mij cC'
ABCD patrat} -> BC,DC,AD=20
Ab=20 }
a)At=6*l^2=6*20^2=2400
V=l^3=20^3=60
b)D'B diagonala cubului
D'B=l radical 3 = 20 radical 3
BD diagonala bazei
BD=l radical 2 = 20 radical 2
BD'=20
Aria tr DD'B=c1•c2(supra 2) =DD'•DB(supra 2)=20•20radical3 (supra 2) (simplifici 20 cu 2) = 10•20 radical 3 = 200 radical 3
La punctul c nu sunt sigura , nu vreau sa gresesti dar eu am folosit teorema celor 3 perependiculare