Across
1
Steepness of a line
4
Part of a line with two endpoints
5
Corner point of a polygon
7
Collection of distinct elements
8
Difference between highest and lowest values
10
Exact correspondence on both sides
11
Closed shape with straight sides
Down
2
Sum divided by count
3
Lines that never intersect
6
Part of a whole number
9
Power to which a number is raised