Di ketahui perbandingan panjang Ab: AC: BC =3 : 4 : 5.jika panjang AB=30cm keliling segitiga ABC

AB : AC : BC = 3 : 4 : 5

Panjang AB = 30 cm
30 cm = 3
30 cm : 10 = 3
(3 x 10 cm) + (4 x 10 cm) + (5 x 10) = 30 + 40 + 50 =120 cm.
Keliling = 120 cm

Panjang AB :

3 = 30
------------ (dikali silang)
4 = x

3x = 30.4
3x = 120
x = 40

panjang BC :

3 = 30
---------- (dikali silang)
5 = x

3x = 150
x = 50

Keliling = AB + AC + BC
= 30 + 40 + 50
= 120cm