Can you explain to me how to find this ? Thank you !

Step-by-step explanation:
with the use of Pythagoras theorem you can find each side of one triangle
I hope this helps!
Answer:
perimeter = 4 x 17 = 68
AC = 2 x √17²-8² = 2 x 15 = 30
Step-by-step explanation:
AC bisect AC at right angle, ABCD is a rhombus
AB = BC = CD = DA
perimeter = 4 x 17 = 68
AC = 2 x √17²-8² = 2 x 15 = 30