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