Answer:
Since the ratio of the angles is 7:2:1, we can write the angles as 7x, 2x, and x, for some x. Since the sum of the angles in a triangles is 180, we have 7x + 2x + x = 180. Combining the x's on the left-hand side, we have 10x = 180. Finally, dividing by 10 gives x = 18.
