You buy 3 bags sand and 2 bags of pea gravel for $21

Don't know how to find x given these segment lengths

The coordinates of vortex a’ are (8,4) (-4,2) (4,-,4) the coordinates of vortex b’ are (6,6)(12,-,12)(12,12) the coordinates of vortex c’ are(-2,,12)(4,12)(12,-4)

Yvaries directly as x. y =90 when x=6. find y when x=13