A square rotated about its center by 360º maps onto itself at 4 different angles of rotation. You can reflect a square onto itself across 4 different lines of reflection.
Answer:
the length of the missing side is 2
Step-by-step explanation:
Use a^2 + b^2 = c^2
a = 4
b = ?
c = 2sqrt5
4^2 + b^2 = (2sqrt5)^2
16 + b^2 = 20
subtract 16 from both sides
b^2 = 4
take the sqrt of both sides
b = 2