In 1852 its height was 29.002ft or 8.839m, while the measuring in 1999 said that it was 29.035ft or 8.850m. That means that it is taller by some 11 meters or 33 feet. That is because it keeps increasing its size since its positioned on such plates that hit each other.
You just made a silly mistake. Angle A is 79, not 89. Just be more careful next time. (Remember, this figure is a cyclic quadrilateral whos opposite angles add up to 180)
