Aturan Cosinus
segitiga ABC
A = balai kota
B = DPRD
C = bank Indonesia
AC = 100 m
AB = 180 m
∠A = 116°
Jarak antara bank Indonesia dan DPRD = BC
BC² = AC² + AB² – 2 . AC . BC cos A
BC² = 100² + 180² – 2 . 100 . 180 cos (90° + 26°)
BC² = 100² + 180² – 2 . 100 . 180 . (- sin 26°)
BC² = 10000 + 32400 + 36000 . 9/10
BC² 42400 + 32400
BC = √74800
BC = 273,496 m
