Question 134188
the diameter of the semicircle is the hypotenuse of the triangle


the segment area is 1/4 the area of the circle minus the area of the triangle
__ the central angle is 90°


the perimeter of the shaded area is the length of the outer side (which is the circumference of the semi-circle)
__ plus the length of the inner side (which is 1/4 the circumference of the large circle)