Question

Difficulty: EasyRight Triangles and the Pythagorean Theorem

A right triangle in the xyxy-plane has vertices at the coordinates (0,0)(0, 0), (15,0)(15, 0), and (15,8)(15, 8). What is the perimeter of this triangle?

  1. A
    17
  2. B
    23
  3. 40Answer
  4. D
    60

Answer

The perimeter of the triangle is 40.
The perimeter of the triangle is the sum of its three side lengths. The horizontal leg has a length of 1515 (from (0,0)(0,0) to (15,0)(15,0)), and the vertical leg has a length of 88 (from (15,0)(15,0) to (15,8)(15,8)). Using the Pythagorean theorem, the hypotenuse has a length of 152+82=225+64=17\sqrt{15^2 + 8^2} = \sqrt{225 + 64} = 17. Summing these three lengths gives a perimeter of 15+8+17=4015 + 8 + 17 = 40.

Step-by-Step Solution

1
Identify the lengths of the two perpendicular legs of the right triangle from the given coordinates.
The horizontal leg lies on the x-axis from (0,0)(0, 0) to (15,0)(15, 0), which has a length of 150=1515 - 0 = 15. The vertical leg runs parallel to the y-axis from (15,0)(15, 0) to (15,8)(15, 8), which has a length of 80=88 - 0 = 8.
The length of horizontal and vertical segments in a coordinate plane can be found by taking the absolute difference of their non-matching coordinates.
2
Use the Pythagorean theorem to calculate the length of the hypotenuse.
The hypotenuse length is 152+82=225+64=289=17\sqrt{15^2 + 8^2} = \sqrt{225 + 64} = \sqrt{289} = 17.
The Pythagorean theorem states that a2+b2=c2a^2 + b^2 = c^2 for any right triangle with legs aa and bb and hypotenuse cc.
3
Calculate the perimeter of the triangle by summing the lengths of all three sides.
15+8+17=4015 + 8 + 17 = 40.
The perimeter of a triangle is the total distance around the boundary, which equals the sum of its three side lengths.

Key Concept

Calculating the perimeter of a right triangle in the coordinate plane by using the Pythagorean theorem to find the hypotenuse.
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