Answer:
17
Step-by-step explanation:
[tex]perimeter = 2(length + breadth) \\ breadth = (perimeter \div 2) - length[/tex]
[tex]72 \div 2 = 36 \\ 36 - 19 = 17[/tex]
y is 17 mm
perimeter formula is p= 2l +2w
19 is width
19+19 = 38
72-38=34
34/2= 17
17 is length
I hope it is right:)
