Explicație pas cu pas:
∢ A = 30°
[tex]AC = 2×BC = 2×12 = 24 \: cm[/tex]
[tex]AB^{2} =AC^{2} -BC^{2} =24^{2} -12^{2} = > AB=12 \sqrt{3} \: cm[/tex]
a)
[tex]P =BC+AC + AB=12+24 + 12 \sqrt{3} = 36 + 12 \sqrt{3}= 12(3 + \sqrt{3}) \: cm [/tex]
b)
[tex]A= \frac{AB \times BC}{2} = \frac{12 \times 12 \sqrt{3} }{2} = 72 \sqrt{3} \: {cm}^{2} [/tex]
c) AD ⊥ AC
[tex]AD = \frac{AB \times BC}{AC} = \frac{12 \times 12 \sqrt{3} }{24} = 6 \sqrt{3} \: cm[/tex]
