tolong dibantu ya.......

19.
• t = 36 cm
• π = 22/7
• Volume = 22.176 cm³
• Diameter = ?
Jawab :
V = πr²t
22176 = 22/7 . r² . 36
22176 = 792/7 . r²
22176 : 792/7 = r²
22176 x 7/792 = r²
196 = r²
√196 = r
14 = r
Diameter = 2r
Diameter = 2(14) = 28



20.
D = 16
r = 8
Luas selimut = 720π
S = ?
Jawab :
Luas selimut = πsr
720π = π x s x 8
720π = 8π x s
720π : 8π = s
90 = s



21.
S = 26
Luas selimut = 260π
t = ?
Jawab :
Luas selimut = πsr
260π = π x 26 x r
260π = 26π x r
260π : 26π = r
10 = r

t² = s² - r²
t² = 26² - 10²
t² = 676 - 100
t² = 576
t = √576
t = 24