Across
1
Reference line in a graph
2
U-shaped curve of a quadratic function
4
The number representing nothing
7
Part of a circle's circumference
8
Single numeral from 0 to 9
10
Three-sided polygon
Down
2
Total distance around a shape
3
System of ordered marks for measuring
5
Longest side of a right triangle
6
Number that divides evenly into another
9
Math using letters for unknown values
11
Round shape with all points equidistant