Across
1
Mathematical statement of equality
4
Closed shape with straight sides
5
Line touching circle at one point
6
Total distance around a shape
7
Space between two intersecting lines
12
Steepness of a line
Down
2
Difference between highest and lowest values
3
Three-sided polygon
4
U-shaped curve of a quadratic function
6
Number divisible only by 1 and itself
8
Power to which a number is raised
9
Exact correspondence on both sides
10
Reference line in a graph
11
Value that does not change