Question

Difficulty: EasyDistance and Midpoint Formulas

In the standard (x,y)(x, y) coordinate plane, what is the distance between the points (1,12)(1, \frac{1}{2}) and (5,72)(5, \frac{7}{2})?

  1. A
    77
  2. B
    252\sqrt{5}
  3. 55Answer
  4. D
    2525
  5. E
    2132\sqrt{13}

Answer

The distance between the two points is 55.
The distance dd between (x1,y1)(x_1, y_1) and (x2,y2)(x_2, y_2) is given by the formula d=(x2x1)2+(y2y1)2d = \sqrt{(x_2-x_1)^2 + (y_2-y_1)^2}. Substituting (1,12)(1, \frac{1}{2}) and (5,72)(5, \frac{7}{2}) gives d=(51)2+(7212)2=42+32=16+9=25=5d = \sqrt{(5-1)^2 + (\frac{7}{2} - \frac{1}{2})^2} = \sqrt{4^2 + 3^2} = \sqrt{16 + 9} = \sqrt{25} = 5.

Step-by-Step Solution

1
Calculate the horizontal change (difference in xx-coordinates)
x2x1=51=4x_2 - x_1 = 5 - 1 = 4
This determines the horizontal leg of the right triangle formed between the two points.
2
Calculate the vertical change (difference in yy-coordinates)
y2y1=7212=62=3y_2 - y_1 = \frac{7}{2} - \frac{1}{2} = \frac{6}{2} = 3
This determines the vertical leg of the right triangle formed between the two points.
3
Apply the Pythagorean theorem (distance formula) to find the distance dd
d=42+32=16+9=25=5d = \sqrt{4^2 + 3^2} = \sqrt{16 + 9} = \sqrt{25} = 5
The straight-line distance is the hypotenuse of the right triangle with legs of lengths 4 and 3.

Key Concept

The Distance Formula
Estimated Time:45s
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