Across
1
Three-sided polygon
2
System of ordered marks for measuring
5
Rectangular array of numbers
6
U-shaped curve of a quadratic function
7
Line touching circle at one point
12
Part of a whole number
Down
2
Rectangle with four equal sides
3
Line crossing from corner to corner
4
Mathematical statement of equality
8
Part of a circle's circumference
9
Steepness of a line
10
Repeated addition
11
Line segment connecting two circle points
13
Single numeral from 0 to 9