Question

Find the area of rectangle ABCD

Answer 1

9514 1404 393

Answer:

  D. 12

Step-by-step explanation:

There are a number of ways to find the area of this rectangle. Perhaps the most straightforward is to find the lengths of the sides and multiply those. The distance formula is useful.

  d = √((x2 -x1)^2 +(y2 -y1)^2)

Using the two upper-left points, we find the length of that side to be ...

  d = √((3 -0)^2 +(3 -0)^2) = √(9 +9) = √18 = 3√2

Similarly, the length of the lower-left side is ...

  d = √((-2 -0)^2 +(-2 -0)^2) = √(4+4) = √8 = 2√2

Then the area of the rectangle is ...

  A = LW

  A = (3√2)(2√2) = 3·2·(√2)^2 = 3·2·2 = 12

The area of rectangle ABCD is 12.

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Other methods include subtracting the area of the corner triangles from the area of the bounding square:

  5^2 -2(1/2)(3·3) -2(1/2)(2·2) = 25 -9 -4 = 12