Across
1
Distance from center to edge of circle
3
Symbol representing unknown value
4
Power to which a number is raised
9
Mathematical statement of equality
13
Line touching circle at one point
Down
2
Single numeral from 0 to 9
3
Amount of space an object occupies
5
Exact correspondence on both sides
6
Part of a circle's circumference
7
Collection of distinct elements
8
Number divisible only by 1 and itself
10
U-shaped curve of a quadratic function
11
Value that does not change
12
Line crossing from corner to corner