Arithmetic of t, r, m = 8 and the average of t, m, r and k = 11. What is the value of k?

Anthony is making a collage for his art class my picking shapes randomly. he has five squares, two triangles, two ovals, and four circles. find p( circle is chosen first)

Astick 2 m long is placed vertically at point b. the top of the stick is in line with the top of a tree as seen from point a, which is 3 m from the stick and 30 m from the tree. how tall is the tree?

The fence around a quadrilateral-shaped pasture is 3a^2+15a+9 long. three sides of the fence have the following lengths: 5a, 10a-2, a^2-7. what is the length of the fourth side of the fence?