i need help with this geometry prblem

my math book is online on this site:
w w w . k e y m a t h . com / D G 3

the class passcode is: 1574-4c524
The chapter is 0
Lesson 0.2
pg. 9
problem number 6

REMEMBER 4-FOLD SYMMENTRY IS NEEDED !!!
URGENT !!!

The question requires 4-fold rotational symmetry.

In a fan with 4 blades, it exhibits 4-fold rotational symmetry. Each blade when turned 90° coincides with the next blade.