Question

cum se rezorva un exercitiu . Un tren I forma de trapez isoscel ABCD cu AB//CD are AB = 16m,CD =28m si inaltimea estr 4 pe 5 din BC

Answer 1

in trapez ducem inaltimile notate cu M si N
MN=AB=16
DM=NC=(28-16)/2=6
in Δ dreptunghic format de inaltime (ΔBNC) aplicam T Pitagora

BC²=NC²+BN² , unde NC=6, BN=4/5BC

6²+(4/5BC)²=BC²
aducem la acelasi numitor comun 5²
6²*5²+4²BC²=5²BC²

6²*5²+16BC²=25BC²
6²*5²=9BC²
6²*5²=3²BC²⇒ BC²=6²*5²/3²⇒BC=6*5/3⇒BC=30/3⇒BC=10