A person in a whispering gallery standing at one focus of the ellipse can whisper and be heard by a person standing at the other focus because all the sound waves that reach the ceiling are reflected to the other person. If a whispering gallery has a length of 104 meters, and the foci are located 20 meters from the center, find the height of the ceiling at the center.

Activity 4 A.) An ellipse is the set of points such that the sum of distance from two fixed point constant. The two fixed points are called foci. • Use graph paper like that shown. It contains two small circles and a series of concentric circles from each. The concentric circles are tangent to each other as shown. • Choose the constant 13. Mark the points at the intersections of circle 9 and circle 4, because 9 + 4 = 13. Continue this process until you have marked the intersection of all circles whose sum is 13. || • Connect the points to form a smooth curve. The curve is an ellipse whose foci are the centers of the two small circles on the graph paper. Circles in the figure are named by letters, circle 1 is circle c, circle 2 is circle d, and so on and so forth

The vertices of an ellipse of eccentricity 0.5 lie at the points (0, +-2). Where do the foci lie?

Use this graph to find each part of the ellipse. A. Orientation. I Select ] B. Center. I Select ] C. Co-Vertices. ( Select ) D. Length of Major Axis. I Select1 E. Length of Minor Axis Seleci 1 F. Foci. I Select] G. Valuc of a. Iselect1 1. Valuc of b. Select1