hitunglah diameter bola jika π = 3,14 dan luas permukaannnya: a.200,96 cm² b.452,16 cm² c.1.256 cm² d.5.024 cm² tolong yaaaaa.

Dik. Luas Permukaan bola :
a) 200,96 cm²
b) 452,16 cm²
c) 1.256 cm²
d) 5.024 cm²

Dit. Diameter Bola tersebut ....?

Jawab....

Luas Permukaan Bola (Lpb) : 4πr²

a) Lpb = 4πr²
@ 200,96 = 4 (3,14) x r²
@ 200,96 = 12,56 x r²
@ r² = 200,96/12,56
@ r² = 16
@ r = √16
@ r = 4cm ⇒ D = 2r = 2(4) = 8cm

b) Lpb = 4πr²
@ 452,16 = 4 (3,14) x r²
@ 452,16 = 12,56 x r²
@ r² = 452,16/12,56
@ r² = 36
@ r = √36
@ r = 6cm ⇒ D= 2r = 2(6) = 12cm

c)Lpb = 4πr²
@ 1.256= 4 (3,14) x r²
@ 1.256 = 12,56 x r²
@ r² = 1256/12,56
@ r² = 100
@ r = √100 = 10cm ⇒ D = 2r = 2(10) = 20cm

d) Lpb = 4πr²
@ 5.024= 4 (3,14) x r²
@ 5.024 = 12,56 x r²
@ r² = 5024/12,56
@ r² = 400
@ r = √400 = 20cm ⇒ D = 2r = 2(20) = 40cm

Semoga membantu... ^_^