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Given that the following coordinates are the vertices of a rectangle, prove that this truly is a rectangle by showing the slopes of the sides that meet are perpendicular (-1, 1), (2,0), (3, 3), and (0,4). Then find the slopes of the diagonals of the previous exercise. Are they perpendicular ?

A. The diagonals of the rectangle are perpendicular.
B. The slopes of the sides that meet are not perpendicular.
C. The quadrilateral is not a rectangle.
D. None

User Agilefall
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1 Answer

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Final answer:

By calculating the slopes of the sides and showing they are perpendicular to each other, and then doing the same for the diagonals, we have proved the quadrilateral is a rectangle, and its diagonals are also perpendicular to each other.

Step-by-step explanation:

To prove whether a quadrilateral with vertices (-1, 1), (2, 0), (3, 3), and (0, 4) is a rectangle, we need to show that the slopes of the sides that meet are perpendicular. The slope is determined by the formula (y2 - y1)/(x2 - x1), which represents the 'rise over run'. Let's calculate the slopes of each side:

  • Side 1 (between (-1, 1) and (2, 0)): slope = (0 - 1) / (2 - (-1)) = -1 / 3
  • Side 2 (between (2, 0) and (3, 3)): slope = (3 - 0) / (3 - 2) = 3
  • Side 3 (between (3, 3) and (0, 4)): slope = (4 - 3) / (0 - 3) = 1 / -3
  • Side 4 (between (0, 4) and (-1, 1)): slope = (1 - 4) / (-1 - 0) = -3

The slopes of Side 1 and Side 4, as well as Side 2 and Side 3, are negative reciprocals of each other, which indicates they are perpendicular. Hence, these sides meet at right angles, and the quadrilateral is a rectangle.

Now, let's find the slopes of the diagonals:

  • Diagonal 1 (between (-1, 1) and (3, 3)): slope = (3 - 1) / (3 - (-1)) = 2 / 4 = 1/2
  • Diagonal 2 (between (2, 0) and (0, 4)): slope = (4 - 0) / (0 - 2) = 4 / -2 = -2

The slopes of the diagonals are also negative reciprocals, which means that the diagonals are perpendicular to each other. This is another characteristic of a rectangle.

Considering the information provided, the answer is 'A. The diagonals of the rectangle are perpendicular'.

User Alexxandar
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