No.16,19,21 Pakai Cara

16.
Luas permukaan tabung = 2.π.r(r+t)
L = 2 x 22/7 x 14(14 + 15)
L = 2 x 22 x 2 x 29
L = 44 x 58
L = 2.552 cm² (C)

19.
Cari panjang garis pelukis
s² = r² + t²
s² = 7² + 24²
s² = 49 + 576
s² = 625
s = √625
s = 25 cm

Luas selimut = π. r. s
L = 22/7 . 7 . 25
L = 22 x 25
L = 550 cm² (B)

21.
Luas permukaan bola padat = 3.π.r²
L = 3 x 3,14 x 10²
L = 9,42 x 100
L = 942 cm² (C)