Across
1
Number with digits after a point
3
Longest side of a right triangle
6
Single numeral from 0 to 9
7
Corner point of a polygon
8
Three-sided polygon
11
Line crossing from corner to corner
12
Distance from center to edge of circle
Down
2
Total distance around a shape
4
Symbol representing unknown value
5
Reference line in a graph
9
Repeated addition
10
System of ordered marks for measuring