If we take half of one of these "pedals" we can see that it is simply 1/4 of a circle with radius 5, subtracted by a triangle. Let's calculate this half-pedal.
That means 4 pedals is equal to:
So.. The area of the shaded region is
Perimeter is even simpler. the half-pedal is just 1/4 of the circumference of the circle. The circumference is just , which means our half pedal is: