### Home > PC > Chapter 7 > Lesson 7.3.3 > Problem 7-127

7-127.

Since (20, 50) is a point of symmetry, it is a point of rotational symmetry and must be on the midline.

Since the *y*-axis is a line of symmetry, the point (−20, 50) must also lie on the curve.

Since (20, 50) is on the midline, the line *y* = 15 must be a lower boundary line.

Use this information to determine the amplitude and make a possible sketch.