mid point formula

What are the coordinates of the midpoint of a segment whose endpoints are (9,12) and (-12,-9)?

conjecture of a circle and triangle

complete the conjecture: The center of a circle inscribed in a triangle is the same point as the intersection of the triangle's _?_.

properties of equality

m<1=35 and the m<2=35. What property justifies the conclusion: m<1=m<2?

circumference and area of a circle

If the circumference of a circle is 30 millimeters, what is its area?

circle circumference and square perimeter

A circle and a square both have an area of 441 square inches. What are their perimeters(circumferences)?