Question

Difficulty: EasyGeometric Figures on the Coordinate Plane

A right triangle is plotted in the standard (x,y)(x, y) coordinate plane. The vertices of the triangle are located at (3,2)(-3, -2), (5,2)(5, -2), and (3,4)(-3, 4). What is the length of the hypotenuse of the triangle?

  1. A
    43\frac{4}{3}
  2. B
    272\sqrt{7}
  3. C
    35\frac{3}{5}
  4. 1010Answer
  5. E
    1414

Answer

10
The distance between the vertices (3,2)(-3, -2) and (5,2)(5, -2) along the horizontal line y=2y = -2 is 5(3)=85 - (-3) = 8 units. The distance between the vertices (3,2)(-3, -2) and (3,4)(-3, 4) along the vertical line x=3x = -3 is 4(2)=64 - (-2) = 6 units. Because horizontal and vertical segments meet at a right angle, they form the legs of a right triangle. Applying the Pythagorean theorem, the length of the hypotenuse is the square root of the sum of the squares of the legs: 82+62=64+36=100=10\sqrt{8^2 + 6^2} = \sqrt{64 + 36} = \sqrt{100} = 10.

Step-by-Step Solution

1
Determine the lengths of the two perpendicular legs of the right triangle on the coordinate plane.
The horizontal leg has a length of 5(3)=85 - (-3) = 8 units, and the vertical leg has a length of 4(2)=64 - (-2) = 6 units.
Because the segment between (3,2)(-3, -2) and (5,2)(5, -2) is horizontal (constant y=2y = -2) and the segment between (3,2)(-3, -2) and (3,4)(-3, 4) is vertical (constant x=3x = -3).
2
Apply the Pythagorean theorem to calculate the length of the hypotenuse.
The hypotenuse length is 82+62=64+36=100=10\sqrt{8^2 + 6^2} = \sqrt{64 + 36} = \sqrt{100} = 10 units.
The Pythagorean theorem states that for any right triangle with legs aa and bb and hypotenuse cc, a2+b2=c2a^2 + b^2 = c^2.

Key Concept

Finding the lengths of segments and applying the Pythagorean theorem on the coordinate plane.
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