no 3 dijawab pliss...... ..

Keliling 1/2 lingkaran = 1/2 x 22/7 x 42 = 66 cm
Keliling persegi = 2 x 21 = 42 cm
Keliling bangun = 66 +42 =108 cm

• Keliling 1/2 lingkaran
= 2 x π x r
= 2 x 22/7 x 21
= 2 x 22 x 3
= 44 x 3
= 132 cm
• keliling persegi
= 4 x S
= 4 x 21
= 84 cm
• keliling bangun
= keliling 1/2 lingkaran + keliling persegi
= 132 + 84
= 216 cm