1. Intr-un Δechilateral , inaltimea este:
h=L* √3/2 => L =h*2√3/3
h=2√3
⇒ L=2√3*2√3/3=12/3=4
⇒ Aria=L²*√3/4=16√3/4=4√3
2.<BAC=30, iar AC=12
in ΔABC avem:
sin <BAC=BC/AC ⇒ 1/2=BC/12 ⇒ BC=12/2=6
cos <BAC=AB/AC ⇒√3/2=AB/12 ⇒AB=12√3/2=6√3
P ABCD=2*(AB+BC)=2*(6√3+6)=12*(√3+1)=12√3+12
3.AB=[tex] \sqrt{(x_2-x_1)^2+(y_2-y_1)^2} [/tex]
unde A(x₁,y₁) si B(x₂,y₂)
⇒AB= [tex] \sqrt{(0-0)^2+(-10+4)^2} = \sqrt{(-6)^2} = \sqrt{36} =6[/tex]