Where do people live in the northern countries of africa?
a) countryside
b) close to water

People in the northern countries of Africa live close to water.

Explanation:

The world's largest desert 'Sahara' has spread over most countries in the north of the African continent. This region is characterized by extreme scarcity of water. The population in these countries is concentrated only in places where there is the availability of water. Compared to the total area, the population in these countries is extremely scarce. Lack of vegetation and a hot, dry climate all throughout the year make living really tough.

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.