geotry

2. perpendicular line segments from the vertex to the line containing the opposite side
3. the point on a line segment or an arc that is equidistant, when measured along the line or arc, from both endpoints
5. a part of a figure cut off by a line or plane intersecting it
6. a part of a line or curve between two points
11. suggest or assume the existence,fact, or truth of (something) as a basis for reasoning, discussion or belief
12. opposite or contrary in position, direction, order, or effect
13. a 2D shape that has 4 sides, 4 corners, and 4 right angles. Opposite sides of a rectangle are the same length, with one pair longer than the other
16. an angle of 180 degrees
17. Angles that measure less than 90 degrees

1. a triangle that has three unequal sides
4. the line or line segment that divides the angle into two equal parts
7. exceeding 90 degrees but less than 180 degrees
8. a rule in algebra or other branches of mathematics expressed by symbols or formulae
9. any of a set of straight lines passing through one point
10. a line joining the midpoint of two sides of a triangle
14. the amount of space within the perimeter of a 2D shape
15. a plane figure with four equal sides and four right (90 degree) angles