Question

URGENTTTT
3.Daca o piramida triunghiulara regulata are muchia laterala de 20 cm si apotema de 16 cm, atunci aria totala este egala cu...cm

Answer 1

notam piramida cu VABC......V-varful ......A,B,C -varfurile bazei
luam o fata laterala de exemplu VAB, VM-apotema,M apartine lui AB, <-unghi,²-la puterea a2a , Al- aria laterala, ap -apotema , Pb- perimetrul bazei,At-aria totala
luam triunghiulΔVMB-dreptunghic
ΔVMB,m(<M)=90grade⇒VB²=VM²+BM²⇒20²=16²+MB²⇒MB²=400-256⇒MB=√144⇒MB=12cm
Al=Pb·ap/2.......Al=72·16/2.......Al=576
Pb=3·L  Pb=3·24......Pb=72
Ab=l²√3/4...........Ab=24²√3/4...........Ab=576√3/4........Al=288√3
At=Al+Ab......At=576+288√3cm