The tip of the leaf is acute. This means that the angle of the leaf with the horizontal is less than 90 degrees. These are different names assigned to special angles that allows mathematicians to classify different mathematical values.
The angle that is more than 90 degrees is called an obtuse whereas that at the perfect 90 degrees is called a right angle. The tips of the leaves are converging to a single point and when you measure the different sides to evaluate the angle they make, we find that it is an acute angle as it is clearly less than 90 degrees.