Across
1
Part of a circle's circumference
3
Exact correspondence on both sides
4
Comparison of two quantities
8
Part of a line with two endpoints
9
Proven mathematical statement
12
Number divisible only by 1 and itself
13
Collection of distinct elements
Down
2
Parts per hundred
5
Value that does not change
6
Reference line in a graph
7
Repeated addition
10
Line segment connecting two circle points
11
Sum divided by count