Why is radioacine dating important when approximating the age of Earth? Scientists can identiy offerent te forms using index fossil records.
Scientists can examine how temperature changes within Earth's interior.
Scientists can determine the order of when rocks formed on Earth.
Scientists can analyze changes in chemical concentration of atmospheric gases.

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. 

Its led to migrationits led to death