Across
1
Round shape with all points equidistant
2
Lines that never intersect
4
The number representing nothing
5
Collection of distinct elements
10
Mathematical rule or equation
11
Math using letters for unknown values
Down
2
Closed shape with straight sides
3
Three-sided polygon
6
Line crossing from corner to corner
7
Number divisible only by 1 and itself
8
Reference line in a graph
9
U-shaped curve of a quadratic function