Vocabulary

4. a parallelogram with opposite equal acute angles, opposite equal obtuse angles, and four equal sides
6. a type of quadrilateral, whose opposite sides are equal and parallel
8. the height of an object or point in relation to sea level or ground level
12. the arithmetic mean position of all the points in the surface of the figure
14. the point at which the three perpendicular bisectors of the sides of a triangle intersect and which is the same distance from each of the three vertices of the triangle
15. the intersection point of the altitudes drawn from the vertices of the triangle to the opposite sides
17. a straight line that divides the angle into two equal or congruent angles
18. a quadrilateral with only one pair of parallel sides

1. a line that bisects a line segment in two equal parts and makes an angle of 90 degrees at the point of intersection
2. having all its sides of the same length
3. is a quadrilateral with two pairs of parallel sides
5. a plane figure with four equal straight sides and four right angles
7. a quadrilateral whose four sides can be grouped into two pairs of equal-length sides that are adjacent to each other
9. at equal distances
10. the middle value in a set of data
11. the point where three bisectors of the interior angles of a triangle intersect
13. (of a straight line) joining two opposite corners of a square, rectangle, or other straight-sided shape
16. having equal angles