Toan s - Quyen Bid 40 Di�n tfch cua m¢t hlnh vu6ng se thay aoi n h lf the nao neu C9 n h hln h vu6ng ta ng them 20%? B a i 41 llm di¢n tlch hhih ch u n h�t, biet rang neu tang 20o/o chieu dai va g iam chieu r¢ng thl di$n tkh ta n g them 20o/o dm2 • Bili 42 Hoi 5% · Khoi l ugng co n g vi$c tang l en 50% n h ung nang suat lao a¢ n g chi ta n g 25% phai ta n g s6 c6ng n h a n len bao nh�eu phan tram ae h o a n th� m h cong vi�c du n g thai h � n ? · Arch i m edes School Aschoo Led u