A triunghi echilateral = l²[tex] \sqrt{3} [/tex] \ 4
h triunghi echilateral = l[tex] \sqrt{3} [/tex] \ 2
A patrat = l²
d = l[tex] \sqrt{2} [/tex]
P = 4·l
Lcerc = 2[tex] \pi [/tex]r
Adisc = [tex] \pi [/tex]r²
Asector(AOB) = [tex] \pi [/tex]r²·n\360°
Aparalelogram = b·h = AB· sin A
P = 2AB + 2BC
Atrapez = (B+b)·h \ 2
linia mijlocie ii trapez = (B+b)\2
P = AB + BC + CD + AD
Aromb = d₁·d₂\2 = l²sin A = B·h
P= 4l
