Răspuns:
Aria paralelogramului = b × h
a) AB = baza
DE perpendicular pe AB =》 DE = h
Aria ABCD = AB × DE
Aria ABCD = 8 × 5
ARIA ABCD = 40 CM^2
b) AD = baza
F = pr lui C pe AD =》 CF perpendicular pe AD =》CF=h
Aria ABCD = AD × CF
Aria ABCD = 5 radical 2 × 3
Aria ABCD = 15 radical 2 cm^2
e)Aici cred ca trebuie sa aplici formula lui Heron
S = radical p × ( p - a ) × ( p - b ) × ( p - c )
S = radical p ×( p-AB) ×( p - BC) × (p-CA)
S = radical p × (p - 13) × ( p- 10 ) ×( p- 9)
p= semiperimetru
p= (AB +BC + CA)/2
p= (13 + 10 + 9)/2
p= 32 : 2
p = 16
S = radical 16 (16-13)(16-10)(16-9)
S = radical 16×3×6×7
S = radical 2016
S =12 radical 14
Aria ABC = 12 radical 14
Aria ABCD = Aria ABC ×2
Aria ABCD = 12 radical 14 × 2
Aria ABCD = 24 radical 14 cm^2
f) Aria ABC = 10 radical 5 cm^2
Aria ABCD = Aria ABC × 2
Aria ABCD = 10 radical 5 × 2
Aria ABCD = 20 radical 5 cm^2
