Plis bantu cara ngerjain nya gimna​

L = πr ( s + r )

75π = πr ( 10 + r )

75 = r ( 10 + r)

75 = 10r + r²

r² + 10r – 75 = 0

misalkan r = x

x² + 10x – 75 = 0

( x – 5 ) ( x + 15 ) = 0

x = 5

x = -15

Nilai jari-jari adalah positif jadi r = 5 cm

jari jari = 5 cm