Plis,tolong bantuin nomor ini 3dan 4 plis
Jawaban:
3.
p = 2x-6
l = x+4
keliling persegi panjang = 2×(p+l)
52 = 2×(2x-6+x+4)
52/2 = 3x-2
26+2 = 3x
28/3 = x
p = 2(28/3)-6
= (56/3)-6
= 56/3 – 18/3
= 38/3
l = (28/3)+4
= 28/3 + 12/3
= 40/3
luas = p×l
= 38/3 × 40/3
= 1520/9
= 168,89 cm²
4.
luas diarsir = 16cm²
sisi diarsir = √16 = 4cm
luas tidak diarsir
= luas persegi panjang – luas diarsir
= p×l – 16
= 14×9 – 16
= 126-16
= 110 cm²