Într-un triunghi echilateral toate cele 3 unghiuri sunt egale,fiecare având 60°.
[tex]a)a+10^{\circ} =60 ^{\circ}[/tex]
[tex]a = 60^{\circ} - 10^{\circ}[/tex]
[tex]a = 50^{\circ}[/tex]
[tex] \frac{b}{2} + 35^{\circ} = 60^{\circ} \: | \times 2[/tex]
[tex]b + 70^{\circ} = 120^{\circ}[/tex]
[tex]b = 120^{\circ} - 70^{\circ}[/tex]
[tex]b = 50^{\circ}[/tex]
[tex]2c - 40^{\circ} = 60^{\circ}[/tex]
[tex]2c = 60^{\circ} + 40^{\circ}[/tex]
[tex]2c = 100^{\circ}[/tex]
[tex]c = \frac{100^{\circ}}{2}[/tex]
[tex]c = 50^{\circ}[/tex]
[tex]b)2a + 20^{\circ} = 60^{\circ}[/tex]
[tex]2a = 60^{\circ} - 20^{\circ}[/tex]
[tex]2a = 40^{\circ}[/tex]
[tex]a = \frac{40^{\circ}}{2}[/tex]
[tex]a = 20^{\circ}[/tex]
[tex]2b - 20^{\circ} = 60^{\circ}[/tex]
[tex]2b = 60^{\circ} + 20^{\circ}[/tex]
[tex]2b = 80^{\circ}[/tex]
[tex]b = \frac{80^{\circ}}{2}[/tex]
[tex]b = 40^{\circ}[/tex]
[tex]2c = 60^{\circ}[/tex]
[tex]c = \frac{60^{\circ}}{2}[/tex]
[tex]c = 30^{\circ}[/tex]
