Across
1
Repeated addition
2
Part of a circle's circumference
4
The number representing nothing
5
Math using letters for unknown values
7
Round shape with all points equidistant
8
Visual representation of data
Down
1
Middle value in an ordered dataset
2
Reference line in a graph
3
U-shaped curve of a quadratic function
6
Collection of distinct elements
9
Lines that never intersect