Răspuns:
Adevarata
Explicație pas cu pas:
In ΔACD aplicam pitagora
AC²=AD²+CD²
225=144+CD²
CD=9
In ΔADB aplicam pitagora
AB²=AD²+DB²
DB²=400-144
DB=16
BC=BD+DC=16+9=25
In ΔABC aplicam reciproca teoremei lui pitagora
AB²=400
AC²=225
BC²=625
Observam ca BC²=AB²+AC²⇒ ΔABC dreptunghic in A⇒ m(∡CAB)=90°
