Hewp meh ples ;w; .............ples

Choice B) 17.5 feet

A = Area of rectangle

L = length

W = width

The formula to use is A = L*W, so we multiply length and width.

We know W = 7 but we don't know what L is.

We know that A = 122.5 is also given

So let's solve for L

A = L*W

L*W = A

L*7 = 122.5     plug in the given values

7*L = 122.5

7*L/7 = 122.5/7     divide both sides by 7

L = 17.5

He should cut 17.5 feet of streamer. Keep in mind that this only applies if Adrian wants to make the streamer completely taut and a straight line across the ceiling/wall. If he wants the streamer to hang down a bit (forming a shape like a rope bridge in a sense), then the streamer's length will have to be a bit longer to account for the extra distance along the curve.