What's the answer and how do u figure out number 5 only

The length of a segment knowing the coordinates of its end points:
(x₁,y₁) and (x₂,y₂) is given by the formula:

Length = √[(x₁ - x₂)² + (y₁ - y₂)²]

T(1,4)  ;   A(4,4)  ;   P(3,0)

a) TA =√[(1-4)²+(4-4)²] → TA = 3
b) AP  =√[(4-3)²+(4-0)²] →AP  = √17 = 1.123
c) TP =√[(1-3)²+(4-0)²] → TA = √20 =  4.472

Perimeter = TA + AP + TP = 8.60