Question

Rezolvarea completa va rog

Answer 1

Sper ca te-am putut ajuta :3

Answer 2

a) Fie BE inaltime, atunci ABED este dreptunghi, AB=DE si AD=BE
/\EBC dreptunghic
m(<EBC) = 135°-90 = 45° rezulta /\EBC isoscel cu EB=EC
EC=DC-DE = 22-12 = 10 cm
EB=10 cm
AD=EB=10 cm

b) A=(B+b)*h / 2=(CD+AB)*BE / 2=34*10/2=340/2=170 cm^2

c) Fie F € AC astfel incat BF_|_AC
d(B;AC) = BF
A(/\ADC) = AD*AC/2 = 10*22/2 = 220/2 = 110 cm^2
A(/\ABC) = A(ABCD) - A(/\ADC) = 170-110 = 60 cm^2
AC*BF/2 = 60 cm^2
AC*BF = 120 cm^2
AC^2 = AD^2 + DC^2 = 10^2 + 22^2 = 100+484 = 584
AC = rad584 = 2*rad146
2 * rad146 * BF = 120 cm^2
rad146 * BF = 60 cm^2
BF = rad3600/rad146
BF = rad(3600/146) = rad(1800/73) = rad(900*2/73) = 30*rad(2/73)