How does population distribution reflect a particular regions economy?

Population distribution shows the pattern of where people live. Population distribution across the globe tend is uneven. Sparsely populated areas have less people and tend to be relatively inhabitable. Densely populated areas have many people living in one area. This shows that the particular has favorable conditions for habitation. Densely populated are therefore suitable for economic productivity. Densely populated have immensely vibrant economies compared to sparsely populated areas.  

I'm pretty sure there's a geometry rule for   anyways, if the triangle is equilateral, and the circle is circumscribed, the circle is outside of the triangle.  to find the area, you need the radius.  the radius should be a straight line from the center of the triangle to any of it's points.  draw lines from the center of the circle to each of the triangle points.  draw three more lines from the center to the middle of the sides of the triangle.  you should now have six separate 30-60-90 triangles inside of your original triangle. use your 30-60-90 rules to solve for the radius, then the circumference. 

The answer is b im not sure