tolong no 2-4 pake cara plis thank sblmnya

2) 20cm + 20cm + 20cm + 20cm = 80cm / 20x4 = 80 cm
3) keliling = (70cm x 2) + (30cm x 2) = 140 + 60 = 200cm
Luas = 70cm x 30cm = 2.100 cm²
4) 4.000cm² : 80cm = 50cm
K = (80x2) + (50x2) = 160 + 100 = 260cm