Question

a woman is walking at the rate of 5 feet per second along the diameter of a circular courtyard. a light at one end of a diameter perpendicular to her path casts a shadow on the circular wall. how fast is the shadow moving along the wall when the distance from the woman to the center of the courtyard is 1/2r , where r feet is the radius of the courtyard.

Answer 1

where is the wall? at the circumference of the courtyard?