Question

1. Keliling ΔABC adalah 38 cm. Jika AB = x cm, BC = (x + 3) cm, dan AC = (x + 5) cm, maka panjang AC =.....
2. Luas sebuah belah ketupat 96 cm², sedangkan panjang diagonalnya (3x + 1) cm dan 12 cm. Nilai x =......

Answer 1

Kell = AB + BC + AC
38   =  x + ( x + 3 ) + ( x + 5 )
38   = 3x + 8
3x   = 30
x     = 10
Maka;
AC = x + 5 = 10 + 5 = 15 cm

Luas = 1/2 x D1 x D2
96    = 1/2 x ( 3x + 1 ) x 12
96    = 6 x ( 3x + 1 )
3x + 1 = 31
3x       = 30
x         = 10

Answer 2

1. K = 38cm
AB = Xcm
BC = (x+3)cm
AC = (x+5)cm
Maka panjang AC =
K = AB + BC + CA
38 = x cm + x + 3 cm + x + 5
38 = 3x cm + 8
38 - 8 = 3x
30 = 3x
x = 30/3
x = 10
AB = x cm = 10 cm
BC = x + 3 cm = 10 + 3 cm = 13 cm
CA = x + 5 cm = 10 + 5 cm = 15 cm

2.
L = 96cm2
panjang diagonal1 = (3x+1)
panjang diagonal2 = 12 cm

Nilai x =
L = 1/2 x D₁ x D₂
L = 1/2 x (3x+1)cm x 12 cm
96cm = 1/2 x 3x + 1 x 12 cm
96 cm = 3x + 1 x 6
96 x 6 - 1 = 3x
16 - 1 = 3x
15 = 3x
x = 5
jadi, nilai x = 5