Question

Un trunchi de piramida patrulatera regulata are L=10cm l=6cm m=13cm
Calculati apotema trunchiului,inaltimea,Aria totala

Answer 1

Ap tr-apotema trunchiului
Ap B-apotema bazei mari
Ap b=apotema bazei mici
h-inaltimea trunchiului
AB-aria bazei mari
Ab aria bazei mici
PB-perimetrul bazei mari
Pb-perimetrul bazei mici

Ap tr=√m²-(L-l\2)²=√13²-(10-6\2)²=√169-4=√165
h=√Ap tr²-(ApB-Apb)²=√165-4=√161
 At=Al+AB+Ab
AB=L²=10²=100
Ab=l²=6²=36
Al=(PB-Pb)*Ap tr\2
PB=4*10=40
Pb=4*6=24
Al=(40-24)*√165\2=16√165\2=8√165
At=8√165+100+36=136+8√165