Respuesta :

Answer:

  63

Step-by-step explanation:

The two tangents to a circle from the same point are the same length.

  SD = SG

  5x +18 = 8x -9

  27 = 3x . . . . . . . . add 9-5x

  9 = x . . . . . . . . . . divide by 3

SG = 8x -9 = 8·9 -9

SG = 63