1st Semester Vocabulary
by Rachel Landis
1. Vertex
1.1. each angular point of a polygon, polyhedron, or other figure.
2. Ray
2.1. a ray is a line with a single endpoint (or point of origin) that extends infinitely in one direction
3. Regular Plolygon
3.1. A regular polygon is a polygon that is equiangular (all angles are equal in measure) and equilateral (all sides have the same length)
4. Isometry
4.1. An isometry is a transformation in which the original figure and its image are congruent.
5. Dilation
5.1. A dilation is a transformation (notation ) that produces an image that is the same shape as the original, but is a different size. A dilation stretches or shrinks the original figure.
6. Reduction
6.1. When an image's size is reduced, but is similar to the original image
7. Enlargement
7.1. a kind of transformation that changes the size of an object. The image created is similar to the object
8. Obtuse Triangle
8.1. An obtuse triangle is one with one obtuse angle (greater than 90°) and two acute angles
9. Scalene Triangle
9.1. A scalene triangle is a triangle that has three unequal sides
10. Corresponding Angles
10.1. The angles that occupy the same relative position at each intersection where a straight line crosses two others. If the two lines are parallel, the corresponding angles are equal
11. Endpoint
11.1. A point at which a line segment or a ray ends
12. Opposite Rays
12.1. Two rays with a common endpoint that point in opposite directions and form a straight line
13. Segment
13.1. a part of a figure cut off by a line or plane intersecting it
14. Center of Dilation
14.1. The center of dilation is a fixed point in the plane about which all points are expanded or contracted
14.1.1. https://www.khanacademy.org/math/geometry-home/transformations/dilations-scaling/v/dilating-from-an-arbitrary-point-example