Pada segitiga ABC a+b=18 a+c=25 c+d=17 tentukan luas segitiga abc?

a + b = 18 <=> b = 18 - a
a + c = 25 <=> c = 25 - a
c + b = 17
25 - a + 18 - a = 17
43 - 2a = 17
2a = 43 - 17
2a = 26
a = 26/2
a = 13 cm

b = 18 - a
b = 18 - 13
b = 5 cm

c = 25 - a
c = 25 - 13
c = 12 cm

a^2 = b^2 + c^2
13^2 = 5^2 + 12^2
169 = 25 + 144
169 = 169 (segitiga siku-siku)

L = 1/2 × b × c
L = 1/2 × 5 × 12
L = 30 cm^2

Jadi luas segitiga ABC adalah 30 cm^2