semua segitiga berikut ini memiliki keliling 57 cm.Tentukan nilai x dan panjang ketiga sisinya

#a
57 = 3x + x + 15
57 - 15 = 4x
42 = 4x
x = 42 / 4
x = 10,5

#b
57 = 3 * (x + 5)
57 / 3 = x + 5
19 - 5 = x
14 = x
x = 14

#c
57 = 5 + (4x - 1) + (2x - 7)
57 - 5 + 1 + 7 = 6x
60 = 6x
x = 10

#d
57 = x + (3x + 7) + (2x + 1)
57 - 7 - 1 = 6x
49 = 6x
x = 8,167

Segitiga
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Cara Mengerjakan :

a. K = 57 cm
--> s1 + s2 + s3 = 57
--> x + 3x + 15 = 57
--> 4x + 15 = 57
--> 4x = 57 - 15
--> 4x = 42
--> x = 42/4
--> x = 10,5 cm

b. K = 57 cm
--> 3s = 57
--> 3 (x + 5) = 57
--> 3x + 15 = 57
--> 3x = 57 - 15
--> 3x = 42
--> x = 42/3
--> x = 14 cm

c. K = 57 cm
--> s1 + s2 + s3 = 57
--> (2x - 7) + 5 + (4x - 1) = 57
--> 6x - 3 = 57
--> 6x = 57 + 3
--> 6x = 60
--> x = 60/6
--> x = 10 cm

d. K = 57 cm
--> s1 + s2 + s3 = 57
--> (2x + 1) + x + (3x + 7) = 57
--> 6x + 8 = 57
--> 6x = 57 - 8
--> 6x = 49
--> x = 49/6
--> x = 8,167 cm

Semoga bisa bermanfaat

HHNS