Across
1
Lines that never intersect
2
Single numeral from 0 to 9
5
Part of a circle's circumference
6
The number representing nothing
8
Line crossing from corner to corner
11
Collection of distinct elements
12
Space between two intersecting lines
Down
2
Number with digits after a point
3
Line touching circle at one point
4
U-shaped curve of a quadratic function
7
Reference line in a graph
9
System of ordered marks for measuring
10
Line segment connecting two circle points