Across
1
U-shaped curve of a quadratic function
4
Part of a line with two endpoints
8
Three-sided polygon
11
Steepness of a line
12
Amount of space an object occupies
Down
2
The number representing nothing
3
Number with digits after a point
5
Rectangle with four equal sides
6
Value that does not change
7
Repeated addition
9
Lines that never intersect
10
Closed shape with straight sides