Across
1
Three-sided polygon
5
The number representing nothing
6
Steepness of a line
9
Total distance around a shape
11
Line segment connecting two circle points
Down
2
Number divisible only by 1 and itself
3
Difference between highest and lowest values
4
Corner point of a polygon
7
Part of a whole number
8
Longest side of a right triangle
10
Number greater than zero