Finding the Area of a Square

If the area of a square with side x is 9, what is the area of a square of side 4x?
A.)  36
B.)  144
C.)  212
D.)  324
E.)  1296

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Area of a square is one side squared, or multiplying length by width, which is the same result.

x² = 9   {squaring one side of the given square equals 9}
x = 3   {took the square root of each side}

The measurement of one side of the given square is 3.

(4x)²   {squaring one side of the other square to find the area}
= [4(3)]²   {substituted 3, for x, into 4x}
= 12²   {multiplied 4 by 3}
= 144   {evaluated the exponent}

B.)  144

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