Across
1
Part of a line with two endpoints
5
Longest side of a right triangle
6
Steepness of a line
7
Rectangle with four equal sides
8
Power to which a number is raised
9
Sum divided by count
Down
2
The number representing nothing
3
Lines that never intersect
4
Number less than zero
10
Divisible by two
11
Closed shape with straight sides
12
Part of a circle's circumference