Across
1
Line crossing from corner to corner
5
Number divisible only by 1 and itself
6
Corner point of a polygon
9
Value that does not change
10
Collection of distinct elements
11
Amount of space an object occupies
Down
2
Lines that never intersect
3
Closed shape with straight sides
4
Mathematical statement of equality
7
Sum divided by count
8
Exact correspondence on both sides