Across
1
Symbol representing unknown value
4
Result of raising a number to an exponent
5
Corner point of a polygon
8
Sum divided by count
9
Exact correspondence on both sides
11
Closed shape with straight sides
12
Steepness of a line
14
Number divisible only by 1 and itself
15
Single numeral from 0 to 9
Down
2
Three-sided polygon
3
Longest side of a right triangle
6
Number with digits after a point
7
Comparison of two quantities
10
Total distance around a shape
13
Divisible by two