First of all, you should regard the concave part of the picture as full. After unfolding, it is equivalent to unfolding a cylindrical surface, and you get a rectangular plane. Its length is the circumference of the headdress, and its width is the height.

So the height is equal to the area of paper divided by the circumference of headdress = 452.16 ÷ 2×π×16 ÷ 452.16 ÷ 32 ÷ 3.14 = 4.5cm.

So the height of the hat is 4.5cm.