What i the width of a rectangle when the length is 19.6 and the diagonal length is 20

Catherine saved some money and plans to add the same amount each week to her savings account. the table represents the number of weeks that she will save, x, and the total amount of money that she will have in her account, y. weeks, x dollars in account, y 4 74 6 86 9 104 11 116 which linear equation represents catherine’s situation?