Across
1
Longest side of a right triangle
8
Closed shape with straight sides
9
Reference line in a graph
10
Rectangular array of numbers
11
Math using letters for unknown values
Down
2
Three-sided polygon
3
Number greater than zero
4
Line crossing from corner to corner
5
Exact correspondence on both sides
6
System of ordered marks for measuring
7
Number divisible only by 1 and itself