In her science classroom Jane noticed that the lengths (in inches) and the weights (in ounces) of the class's pet snakes were directly related by the equation y = kx, where x is the length and y is the weight. Use the information in the table to find k, the constant of proportionality.

C) 30.0 ounces

Step-by-step explanation:

Use one of the ordered pairs that are given to find the value of 'k', the CONSTANT of variation. This number will not change, hence the word 'constant'.

15 = k*6; dividing both sides by 6 we get k = 2.5; The equation used for the table is y = 2.5x

You can find any value now by using this formula.

y = 2.5*12

y = 30

we have three similar triangles, because each has a right angle and shares an angle.   let's write the angles in order: opposite to short leg, long leg, hypotenuse.

cab similar to bad similar to cbd

or as ratios,

ca: ab: cb = ba: ad: bd = cb: bd: cd

we also know

ac = ad + cd

(ad+cd): ab: cb = ba: ad: bd = cb: bd: cd

(ad+cd)/cb=cb/cd

we have cb=6, ad=5 and seek x=cd.

we reject the negative root and conclude x=4

answer: 4