diketahui segitiga ABC,

Mapel : Matematika
Kelas : VII SMP
Bab : Sudut

Pembahasan :
Total Sudut Segitiga = 180°
< A + < B + < C = 180°
(3x + 7)° + (2x + 5)° + x° = 180°
6x + 12 = 180
6x = 180 - 12
6x = 168
x = 28

< A , < B , < C
= (3x + 7)° , (2x + 5)° , x°
= (3.28 + 7)° , (2.28 + 5)° , 28°
= 91° , 61° , 28°

∠A + ∠B + ∠C = [tex] 180^{0} [/tex]
[tex]3x + 7 + 2 x + 5 + x =[/tex] [tex] 180^{0} [/tex]
[tex]6x + 12 = 180^{0} [/tex]
[tex]6x = 168^{0} [/tex]
[tex]x = 28^{0}[/tex]

∠A = [tex](3x + 7)^{0} = (28.3 + 7)^{0} = 91^{0} [/tex]
∠B = [tex](2x + 5)^{0} = (56 + 5)^{0} = 61^{0}[/tex]
∠C = [tex]28^{0} [/tex]