Across
1
Part of a line with two endpoints
3
U-shaped curve of a quadratic function
4
Part of a circle's circumference
7
Longest side of a right triangle
8
System of ordered marks for measuring
11
Rectangle with four equal sides
Down
2
Math using letters for unknown values
5
Part of a whole number
6
Proven mathematical statement
9
Total distance around a shape
10
Sum divided by count