Across
1
Mathematical statement of equality
5
Repeated addition
6
Mathematical rule or equation
8
Part of a circle's circumference
9
Three-sided polygon
11
Collection of distinct elements
Down
2
U-shaped curve of a quadratic function
3
Distance from center to edge of circle
4
Lines that never intersect
7
Single numeral from 0 to 9
10
Line crossing from corner to corner