besar sudut abc adalah

Kelas 7 Matematika
Bab Garis dan Sudut

3x + 10° + 6x - 5° = 140°
9x = 140° - 5°
x = 135°/9
x = 15°

Sudut ABC
= 3x + 10°
= 3 . 15° + 10°
= 45° + 10°
= 55°

≡ penyelesaian :

⇒Tentukan nilai x :

↬∠B + ∠C = ∠A
↬( 3x + 10 )° + ( 6x - 5 )° = 140°
↬3x + 10° + 6x - 5° = 140°
↬3x + 6x = 140° - 10° + 5°
↬9x = 140° - 5°
↬9x = 135°
↬x = 135° / 9
↬x = 15

⇒maka, besar ∠ABC :

↬∠ABC = ( 3x + 10 )°
↬∠ABC = ( 3( 15 ) + 10 )°
↬∠ABC = ( 45 + 10 )°
↬∠ABC = 55° [tex]~[/tex]