Across
1
Difference between highest and lowest values
2
Reference line in a graph
3
Three-sided polygon
6
Closed shape with straight sides
11
Part of a circle's circumference
12
Proven mathematical statement
Down
2
Math using letters for unknown values
4
Exact correspondence on both sides
5
Rectangle with four equal sides
7
Line touching circle at one point
8
Distance from center to edge of circle
9
The number representing nothing
10
Corner point of a polygon