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Bunuel
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I don't quite follow the explanation given either. However, I think a simpler way to solve may be just to realize that orbit=circumference. So if the radius increases by r/2 how much does the circumference increase. And since circumference= pi*di if the radius increases by pi/2 multiply by 2 to get diameter=pi, and then plug into circumference equation you get pi*pi or pi^2.
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Details of Bunuel's method:

The length of the orbit is asking for the circumference.

If the new orbit (circle) is increased by π/2 then the circumference of this would be 2π(R + π/2). The question asks for the increase (or the difference) of the new circumference to the original circumference. Thus 2π(R + π/2) - 2πR. When using distributives it would = 2πR + 2π^2 / 2 - 2πR. The 2π^2 /2 cancels out to be π^2 and 2πR - 2πR cancels out. Thus π^2 becomes the answer.

Hope this helps.
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You can also pick smart numbers:

\(r1=π\)
\(c1=2rπ=2π^2\)

\(r2=\frac{3π}{2}\)
\(c2=2rπ=2\frac{3π}{2}π=3π^2\)

\(diff=3π^2-2π^2=π^2\)
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SQUINGEL
i am lost..............please help


Easy breezy word problem with some geometry

Lenght of the orbit is calculated by = 2pi*r (circumference)
Then you just have to add the formula above pi/2 which will give

2*pi*(r+pi/2) = 2pi*r+pi^2

So, pi^2 is the answer
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Initial length of the earth's orbit (Let this be P1) = Perimeter of a circle

P1 = 2πr

We want to know the new length of the earths orbit (new perimeter, say P2) if the radius increases BY π/2

P2 = 2π(r+π/2)

P2 = 2πr + 2π^2/2

P2 = 2πr + π^2

P2 = P1 + π^2

Hence, earths orbit increases by π^2 meters

Answer choice (E)
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