Tentukan panjang dari unsur tabung yang ditanyakan

Tentukan panjang dari unsur tabung yang ditanyakan

Jawaban:

$rm r = 7.000$ cm = $70$ m
$rm l_{: selimut} = 264.000$ cm² = $26,4$ m²
$rm l_{:alas} = 154.000.000$ cm² = $15.400$ m²
$rm l_{:permukaan} = 308.264.000$ cm² = $30,826,4$ m²

Penjelasan dengan langkah-langkah:

Mencari $text{r}$

$begin{aligned} rm v &= rm pi {r}^{2}t \ rm 294pi& = rmpi {r}^{2} 6 \ rm 294.000.000pi& = rmpi {r}^{2} 6 \ frac{294.000.000pi}{6pi} & = rm {r}^{2} \ sqrt{49.000.000} & = rm {r}\ bold{7.000}& = rm r end{aligned}$

–

Mencari $rm l_{: selimut}$

$begin{aligned} rm l_{:selimut} &= rm 2pi rt\ rm l_{:selimut}& = 2 times frac{22}{7}times 7.000 times 6\ rm l_{:selimut} & = 44 times 6.000\ rm l_{:selimut}& = bold{ 264.000} end{aligned}$

–

Mencari $rm l_{:alas}$

$begin{aligned} rm l_{:alas} &= rm pi {r}^{2} \ rm l_{:alas}& = frac{22}{7} times {(7.000)}^{2} \ rm l_{:alas}& = frac{22}{7} times 49.000.000\ rm l_{:alas}& = bold{ 154.000.000} end{aligned}$

–

Mencari $rm l_{:permukaan}$

$begin{aligned} rm l_{:permukaan} &= rm 2pi r(r + t)\ rm l_{:permukaan}& = 2 times frac{22}{7} times 7.000(7.000 + 6)\ rm l_{:permukaan} & = 44.000(7.006)\ rm l_{:permukaan}& = bold{308.264.000} end{aligned}$

Diketahui:

V = 294π m³ =
t = 6 cm = 0,06 m

Ditanyakan:

r = … m?
L = … m²?

Penyelesaian:

Jari-jari

V = πr²t

294π = π . r² . 0,06

294 = r² . 0,06

r² = 294 ÷ 0,06

r² = 4.900

r = √4.900

r = 70 m

Luas permukaan

Lp = 2πr (r + t)

Lp = 2 × 22/7 × 70 ( 70 + 0,06)

Lp = 2 × 22 × 10 × 70,06

Lp = 44 × 10 × 70,06

Lp = 30.826,4 m²