Jawaban:

13.) r = 14 cm

π = 22/7

V = 4/3 × π × r³

= 4/3 × 22/7 × 14³

= 4/3 × 22/7 × 2.744

= 4/3 × 22 × 392

= 4/3 × 8.624

= 34.496/3

= 11.498,667 cm³

14.) 1/2 x luas alas x tinggi

= 1/2 x 11 x 9 x 20

= 1/2 x 99 x 20

= 990cm³

16.)L = ½ × d1 × d2

=L = ½ × 15 cm × 10 cm

=L = 75 cm²

=V = ⅓ × Luas alas × Tinggi limas

=500 cm³ = ⅓ × 75 cm² × Tinggi limas

=500 cm³ = 25 cm² × Tinggi limas

=Tinggi limas = 500 cm³ ÷ 25 cm²

=20 cm

17.)Luas permukaan

=luas = 4 x π x r²

=154 = 4 x 22/7 x r²

=154 = 88/7 x r²

=r² = 154 x 7/88

=r² = 12,25

= r = √ 12,25

=r = 3,5 cm

18.)Luas selimut tabung = 2 x π x r x t

=2 x π x r x t = Luas selimut tabung

=2× 22/7 × r x 20 = 660

=880/7 x r = 660

=r= 660 x 7/880

=r = 5,25 cm

Jari-jari tabung 5,25 cm.

20.)V tabung = πr²t

= 22/7 x 14 cm x 14 cm x 18 cm

= 11.088 cm³