Respuesta :

Answer:

3

Step-by-step explanation:

18+18 = 36. 42-36 = 6. 6 / 2 = 3

Answer:

s = 3

Step-by-step explanation:

2 sides measure 18 so

42- 18 - 18 = 6

2 sides  =  s

so 2s = 6

divide both sides by 2 and taaadaaa

s = 3