Geometry

1. -- a line segment connecting two points of the interior can go outside the polygon; at least one of the interior angles is greater than 180 degrees
2. -- the point in the middle of the circle or sphere
5. -- a triangle with three acute angles
6. -- congruent angles formed by two parallel lines cut by a transversal; located on opposite sides of the transversal between the parallel lines
7. -- an angle measuring between zero and 90 degrees
8. -- the perimeter of a circle
9. -- the top and bottom parallel polygonal faces
10. -- the height of a 2-D or 3-D geometric figure measured perpendicularly from the center of the top face or point to the center of the base

1. -- two or more angles that sum to 90 degrees
3. -- a 2-D figure; the set of all points at a given distance from the center
4. -- a cone or cylinder with circles for base(s)
5. -- congruent angles formed by two parallel lines cut by a transversal; located on opposite sides of the transversal outside the parallel lines
8. -- a curve that can be traced without lifting the pencil, has the same starting/stopping points and may cross itself (creates an inside and outside of the curve)