How do wind and water change the land form
Tell me

In dry areas, wind is a powerful cause of weathering and erosion. ... You learned how water changes Earth's surface through weathering, erosion, and deposition. Wind also causes these processes. This is especially true in dry, open areas where strong winds are common and a lot of rock is exposed.

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.