consideram fiecare fata laterala un trapez cu
baza mica =8 cm
baza mare=28 cm
latura neparalela =26 cm
calculam inaltimea acestui trapez
(28-8)/2=10
h=√(26²-10²)=√676-100)=√576=24 cm
A trapez=(8+28)×24/2=36×12=432 cm²
A laterala abajur =432×4=1728 cm²
Apanza=50²=2500 cm² sunt suficienti