39.58 and this is because the radius is half of the diameter so the diameter can be though of as 2r. The formula is C= 2pi r
X = 47 + 9y
xy = 1860
y(47 + 9y) = 1860
47y + 9y² = 1860
9y² + 47y - 1860 = 0
> using a quadratic equation solver on a calculator but you can also use the quadratic equation = [-b+/- √(b²-4ac)]/(2a)
> only integer solution is x = 12
12y = 1860
y = 155
integers are 12 and 155
The ratio is 1:4
She could use...
4 gems and 16 flowers... 4 x 4 = 16
7 stickers and 28 glue dots... 7 x 4 = 28