To determine how many chocolate pyramids Dorothy can make, we need to follow these steps:

1. Calculate the total volume of chocolate Dorothy has:

   • Each bar of chocolate contains 6 cubic inches.
   • Dorothy has 20 bars of chocolate. $\text{Total volume of chocolate} = 20 \times 6 = 120 \text{ cubic inches}$

2. Calculate the volume of one chocolate pyramid:

   • The formula for the volume $V$ of a pyramid with a square base is: $V = \frac{1}{3} \times \text{base area} \times \text{height}$
   • The base area is 1 square inch, and the height is 2 inches. $V = \frac{1}{3} \times 1 \times 2 = \frac{2}{3} \text{ cubic inches}$

3. Determine the number of pyramids that can be made:

   • We need to divide the total volume of chocolate by the volume of one pyramid. $\text{Number of pyramids} = \frac{120 \text{ cubic inches}}{\frac{2}{3} \text{ cubic inches/pyramid}} = 120 \times \frac{3}{2} = 180$

Therefore, the largest number of pyramids Dorothy can make from the 20 bars of chocolate is:

$\boxed{180}$

Would you like details or have any questions?

Here are 5 numbered questions you may consider:

1. How do you calculate the volume of a rectangular prism?
2. What is the formula for the surface area of a pyramid?
3. How do you determine the volume of a cylinder?
4. What are the properties of similar pyramids?
5. How do you find the height of a pyramid if the volume and base area are known?

Tip: Always verify the units of measurement when solving geometry problems to ensure consistency and accuracy.