Respuesta :

mhanifa

Answer:

  • 5 cm

Step-by-step explanation:

  • AB = DC as opposite sides of rectangle.
  • DE = AD as equal sides of isosceles triangle
  • DE + EC = DC segment addition postulate

Now substitute the values and find the length of EC:

  • EC = AB - AD
  • EC = 4p + 3 - (3p - 1)
  • EC = 4p + 3 - 3p + 1
  • EC = p + 4

Given p = 1

  • EC = 1 + 4 = 5 cm