Why is the systems approach so useful in studying both natural and artificial processes? Can you think of examples of artificial (i. e., human-built) systems other than those given in the text? Are they open systems or closed systems? (Think about the ma Cerials and energy in them . )

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. 

Answerencourage alternative timber sources,increase public awareness of the forests,increase research into forestry,involve local communities in forest projectsalso one of the main initiatives of the 1977 act was to introduce a new approach to forest management known as selective management system, this is recognised as one of the most sustainable approaches to tropical forestry management in the world

Ithink its d.stratum

Most topographic maps, the index contour lines are generally darker and are marked with their elevations.