Jawabanmu

2014-04-23T17:21:14+07:00
l = √p² - ( R - r )²
  = √70² - ( 25 - 8 )²
  = √4900 - ( 17 )²
  = √4900 - 289
  = √4611
  = 67.9043++

l = garis singgung persekutuan luar
R = jari2 lingkaran 1
r = jari2 lingkaran 2