The coordinates of two vertices of a rectangles are(3,7)and (-4,7)if the rectangle has a perimeter of 30 unit what are the possible coordinates of its other two vertices

This is a map of the mars exploration rover opportunity predicted landing site on mars. the scale is 1cm : 9.4km. what are the approximate measures of the actual length and width of the ellipse? i mostly need to know how to set it up : )