To determine how many heads tall a figure is in a drawing, you typically measure the total height of the figure and divide it by the height of the head. In traditional figure drawing, an average adult human figure is about 7 to 8 heads tall. However, the exact ratio can vary depending on the artistic style and proportion being used.
If you have a specific drawing in mind, you would need to measure the height of the woman in the drawing and the height of her head to make this calculation. If you can provide a description or details about the drawing, I could offer more insight!