Math

1. two angles that, when added together, equal 180 degrees, essentially forming a straight line
3. having balance, proportion, and harmony, or being able to divide an object into identical parts
6. a polygon with three sides and three corners, or vertices. It's
12. triangle that has all its sides of different lengths
13. two angles have a common vertex and a common side and don't overlap.
15. the side opposite the right angle
18. a pair of adjacent, supplementary angles
19. shape where all sides are equal in length
20. a pair of angles formed when two lines intersect, where they are located directly opposite each other at the intersection point, and are always congruent (equal in measure) to one another

2. Any statement that is assumed to be true on the basis of reasoning or discussion
4. an angle that measures exactly 90 degrees
5. if their measures add to 90 degrees
7. triangle that has two equal sides.
8. states that a quantity is equal to itself. For example, for any number a, a = a. In geometry, a segment is congruent to itself.
9. a polygon having four sides, four angles, and four vertices
10. a quadrilateral with two pairs of parallel sides.
11. An angle smaller than the right angle
14. a rule, principle, or statement that can be proved to be true
16. for three elements a, b, c in set A, if a = b and b = c, then a = c. Here, equality '='
17. one in which the three interior angles all measure 60 degrees