Across
1
Space between two intersecting lines
4
Round shape with all points equidistant
5
Collection of distinct elements
6
Single numeral from 0 to 9
7
Total distance around a shape
11
Math using letters for unknown values
12
Line crossing from corner to corner
13
Part of a circle's circumference
Down
2
Power to which a number is raised
3
Split into equal parts
4
Line segment connecting two circle points
5
Rectangle with four equal sides
8
Line touching circle at one point
9
Three-sided polygon
10
U-shaped curve of a quadratic function