Across
1
Line touching circle at one point
5
Steepness of a line
8
Longest side of a right triangle
9
Result of multiplication
10
System of ordered marks for measuring
12
Lines that never intersect
Down
2
Number less than zero
3
Three-sided polygon
4
The number representing nothing
6
Part of a whole number
7
Line crossing from corner to corner
11
Part of a line with two endpoints