What is the largest number of right angles possible in a pentagon?

In a pentagon, the sum of the interior angles is 540 degrees. Since each right angle is 90 degrees, the maximum number of right angles that can fit within this total is 4, which would account for 360 degrees. The fifth angle would then be 180 degrees, which is not possible in a polygon. Therefore, the largest number of right angles possible in a pentagon is 4.