Across
1
Exact correspondence on both sides
4
Part of a circle's circumference
6
Total distance around a shape
7
Number divisible only by 1 and itself
9
Reference line in a graph
12
Line segment connecting two circle points
13
Symbol representing unknown value
Down
2
The number representing nothing
3
Longest side of a right triangle
4
Math using letters for unknown values
5
Middle value in an ordered dataset
8
Result of multiplication
10
Comparison of two quantities
11
Steepness of a line