tolong bantu+caranya

Keliling = KL + LM + KM
25 = (LM - 1) + (4 + KM) + KM
25 = (4 + KM - 1) + (4 + KM) + KM
25 = 3 + KM + 4 + KM + KM
25 = 7 + 3KM
18 = 3 KM
KM = 6 cm

Panjang KL :
= LM - 1
= 4 + KM - 1
= 3 + KM
= 3 + 6
= 9 cm (c)

KL=LM-1cm

LM=KM+4cm

KM=LM-4cm

                 K=KL+LM+KM
          25cm=(LM-1cm)+LM+(LM-4cm)
25cm+5cm=3LM
         30cm=3LM
             LM=30cm/3
             LM=10cm

KL=LM-1cm
     =10cm-1cm
     =9cm(C)