input: Write a python function to calculate the perimeter and area of a triangle given its three sides.
  assert calculate_triangle(3, 4, 5) == (12, 6.0)
  assert calculate_triangle(6, 8, 10) == (24, 24.0)
  assert calculate_triangle(7, 24, 25) == (56, 84.0)
output: def calculate_triangle(a, b, c):
      perimeter = a + b + c
      s = perimeter / 2
      area = (s * (s - a) * (s - b) * (s - c)) ** 0.5
      return (perimeter, area)