perhatikan gambar berikut! besar sudut ABC adalah... A.140° B.100° C.80° D.40° tolong di jawab beserta caranya

Sudut , Kelas VII

ABC = 180 - 5x
ACB = 180 - 7x

krn segitiga

180-5x + 180-7x + 60 = 180
420 - 12x = 180
12x = 420-180
12x = 240
x = 20°

ABC = 180-5(20)
= 180 - 100
= 80°

c.