Question

In ∆ dreptunghuic ABC se cunosc m(unghiului A)=90 grade,AB=12 cm si BC=20 cm. Daca AD perpendiculara BC,D apatine( BC),calculati inaltimea AD si perimetrul ∆ABC

Answer 1

AB =12 cm
BC =20cm

AB^2 =BC*BD
12^2 =20*BD
144 =20*BD
BD =144:20 =7.2 cm

DC =20-7.2 =12.8 cm

AD^2 =BD*DC
AD^2 =7.2*12.8 =92.16 cm

AC^2 BC*DC
AC^2 =20*12.8=256
AC =16 cm
P =12+16+20 =48 cm