Across
1
Amount of space an object occupies
3
Collection of distinct elements
4
Exact correspondence on both sides
5
Proven mathematical statement
7
Reference line in a graph
10
Mathematical rule or equation
13
Lines that never intersect
Down
2
U-shaped curve of a quadratic function
3
Part of a line with two endpoints
6
Distance from center to edge of circle
8
Three-sided polygon
9
Result of addition
11
Value that does not change
12
Line touching circle at one point