In the images you provided, we have several formulas related to calculating the area of polygons and circles as well as the circumference of a circle. Here's a breakdown of each formula:

1. Area of a Triangle:
   $A = \frac{1}{2}bh$ where $b$ is the base and $h$ is the height of the triangle.

2. Area of a Rectangle:
   $A = bh$ where $b$ is the base (or width) and $h$ is the height (or length) of the rectangle.

3. Area of a Circle:
   $A = \pi r^2$ where $r$ is the radius of the circle.

4. Circumference of a Circle:
   $C = 2\pi r$ where $r$ is the radius of the circle.

Each of these formulas helps you calculate either the area (for triangles, rectangles, and circles) or the circumference (for circles).

Would you like a detailed example or further explanation of how these formulas are applied?

Here are 5 follow-up questions to explore this topic further:

1. How do we apply these formulas to composite shapes that include more than one polygon?
2. What is the significance of $\pi$ in the area and circumference formulas for a circle?
3. How do you calculate the perimeter of a rectangle or other polygons?
4. Can the formula for a triangle's area be used for any type of triangle, or only right triangles?
5. What would be the result if the radius of a circle doubled in terms of its area and circumference?

Tip: Always make sure to use the correct units (e.g., square meters for area, meters for perimeter) to ensure consistency in your calculations.