Question

Sebuah lingkaran memiliki luas 154 π cm². Berapakah panjang keliling lingkaran tersebut?​

Answer 1

Materi : Lingkaran

Jari - Jari Lingkaran

L = πr²

154π cm² = πr²

r² = 154 cm²

r = 12,4096..

r ~ 12,4 cm

Keliling Lingkaran

K = πd

K = 3,14 . 12,4 cm

K = 38,936 cm

Semoga bisa membantu

[tex] \boxed{ \colorbox{darkblue}{ \sf{ \color{lightblue}{ answered\:by\: BLUEBRAXGEOMETRY}}}} [/tex]

Answer 2

Verified answer

Bangun Datar

[Lingkaran]

..

[tex]\begin{gathered}\boxed{ \begin{array}{lr} \boxed{\large{\sf{\begin{array}{rl} \sf{L} &=\sf{ \pi \times r \times r} \\ \hline\sf K &= \sf{\pi \times d} \end{array}}}}\\ \\\sf{Keterangan \ \: :}\\ \begin{aligned} \sf{ L} &= \sf{ Luas~Lingkaran}\\ \sf{ K } &= \sf{Keliling~Lingkaran} \\\sf{ \pi } &= \sf{ Konstanta~Lingkaran } \\ \sf{ r } &= \sf{ Jari-Jari }\\ \sf{ d } & =\sf{ Diameter } \end{aligned} \end{array}} \begin{aligned}&~~\to \sf{r = ½d}\\ &~~\to \sf{\pi =\frac{22}{7} \: jika \: r ~atau~d = kelipatan \: 7} \\&~~\to \sf{\pi =3.14 \: jika \: r ~atau~d \ne kelipatan \: 7}\end{aligned}\end{gathered}[/tex]

Penyelesaian Soal

[tex]\begin{aligned} Keliling &= \pi \times d \\&= \pi \times \left(2 \times r\right) \\&= \pi \times \left(2 \times \frac{\sqrt{154~cm^2} \pi}{\pi} \right) \\&= 3.14 \times (2 \times \sqrt{154}~cm) \\&= 3.14 \times 2\sqrt{154}~cm \\&= 6.28\sqrt{154}~cm \\& \approx 6.28 \times 12.4~cm \\& \approx \boxed{\bold{\underline{ 77,93~cm}}}\end{aligned}[/tex]

[tex]\boxed{\colorbox{ccddff}{Answered by Danial Alf'at | 23 - 06 - 2023}}[/tex]