Question

1)Un cerc are raza de 6cm.Cat e latura hexagonlui regulat inscris in cerc?
2)In triunghiul ABC , AD_l_BC masura ∠C=30° masura ∠ABC=60° BD=6cm
Calculati a) Aria triunghi ABC b) Perimetru ABC

Answer 1

1.Latura hexagon=6 cm
2. triunghiul ABC este dreptunghic
in triunghiul ABD
cos 60⁰=BD/AB
1/2=6/AB
AB=12
AD=√(12²-6²)=√144-36)=√108=6√3
sin 30⁰=AD/AC
1/2=6√3/AC
AC=2x6√3=12√3
A=ABxAC/2=12x12√3/2=72√3 cm²
A=BCxAD/2
72√3=BCx6√3/2
144=BCx6
BC=24 cm
P=12+12√3+24=36+12√3=12(3+√3) cm