front 1 Pi (π)  back 1 3.14 
front 2 Circumference of a circle  back 2 πd (3.14 x diameter) 
front 3 Area of a circle  back 3 πr2 (3.14 x radius squared) 
front 4 Perimeter of a square  back 4 side + side + side + side

front 5 Area of a square  back 5 s2

front 6 Perimeter of a rectangle  back 6 2length + 2width

front 7 Area of a rectangle  back 7 lw

front 8 Perimeter of a triangle  back 8 s + s + s 
front 9 Area of a triangle  back 9 1/2 base x height

front 10 Surface area of a cylinder  back 10 2πr2 (2 x 3.14 x radius squared) + 2πrh (2 x 3.14 x radius x height) 
front 11 Volume of a cylinder  back 11 πr2h (3.14 x radius squared x height) 
front 12 Surface area of a rectangular prism  back 12 2(lw) + 2(lh) + 2(wh) 
front 13 Volume of a rectangular prism  back 13 lwh

front 14 Volume of a cone  back 14 1/3 πr2h (3.14 x radius squared x height) 