Question

Va rog mult sa ma ajutati

Answer 1

Răspuns:

G=12 dm

Al=72·pi dm²

At=90·pi dm²

V=108·pi dm³

Explicație pas cu pas:

Aria ABB'C'=72 dm²; R=25%G

Aria ABB'C'=72 dm²=D·h=D·G  ⇒D=2·R=2·25G/100=50G/100=G/2  ⇒

Aria ABB'C'=D·G=(G/2)·G=G²/2=72  ⇒G²=72·2=144  ⇒G=√144=12 dm.

D=G/2=12/2=6 dm  ⇒R=D/2=6/2=3 dm.

Al=2·pi·R·G=2·pi·3·12=72·pi dm²

At=Al+2·Ab=72·pi+2·(pi·R²)=72·pi+2·(pi·3²)=72·pi+2·(pi·9)=72·pi+18·pi=

=90·pi dm²

V=pi·R²·G=pi·9·12=108·pi dm³