7w - 15 = 48 what does the w stand for

Aphoto of a painting measured 13 x 17 inches the scale of the photo to the original painting is 1 inch to 3 inches. what is the size of this painting

Given that de, df, and ef are midsegments of △abc, and de=3.2 feet, ef=4 feet, and df=2.4 feet, the perimeter of △abc is .

An objects motion is described by the equation d= 4sin (pi t) what will the height of the object be at 1.75 seconds?