Double integrate help

Homework Statement

Using polar coordinates, evaluate the integral which gives the area which lies in the first quadrant below the line y=7,and between the circles x^2 + y^2 = 196 and x^2 - 14x + y^2 = 0.

The Attempt at a Solution

i tried to double integrate from 0<theta<pi/2, 7-14cos(theta)<r<7 with rdrd(theta) but that was not the correct answe, can someone tell me with i did wrong with the r values

Dick