Practice question

What is the length of chord formula?

  1. LC = R * I
  2. LC = 2 * R * sin(I / 2)
  3. LC = πR
  4. LC = R + I

Answer: B — LC = 2 * R * sin(I / 2)

The formula for the length of a chord, which is calculated using the radius and the angle subtended at the center of the circle, is expressed as LC = 2 * R * sin(I / 2). In this context, "LC" represents the length of the chord, "R" is the radius of the circle, and "I" is the angle in radians. This formula derives from the basic principles of trigonometry and geometry. When you have a circle and you draw a chord, you can visualize that chord forming two right triangles when you draw lines from the ends of the chord to the center of the circle. The angle I is halved, and the sine function relates the opposite side of these triangles (half the chord) to the hypotenuse (the radius). Multiplying this by 2 gives the entire chord length. Being able to calculate the length of a chord is crucial in highway construction and design, as it assists in understanding curve layout, slope tolerance, and alignment for safe vehicular movement.

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