Across
1
Three-sided polygon
2
Symbol representing unknown value
4
Collection of distinct elements
6
Mathematical rule or equation
7
Result of addition
Down
2
Amount of space an object occupies
3
Number divisible only by 1 and itself
4
Part of a line with two endpoints
5
Middle value in an ordered dataset
8
Closed shape with straight sides
9
Distance from center to edge of circle
10
Line crossing from corner to corner
11
Space between two intersecting lines