Math Problem Statement

Point 1 N = 10123.56 E = 10156.92 Point 2 N = 9905.56 E = 9923.57

Compute the coordinates of a point located 309.92 ft. from point 1 at a clockwise horizontal angle of 312 d 46’ 23” from a line from 1 to 2.

Solution

To solve this problem, we need to:

  1. Compute the azimuth (bearing) of the line from Point 1 to Point 2.
  2. Adjust the azimuth by the given angle (312° 46' 23") to find the direction of the new line.
  3. Compute the new coordinates using the adjusted azimuth and the distance of 309.92 feet.

Step 1: Compute the Azimuth from Point 1 to Point 2

The azimuth is the angle measured clockwise from the North direction to the line connecting the two points.

We can calculate it using the formula:

Azimuth=arctan(ΔEΔN)\text{Azimuth} = \arctan\left(\frac{\Delta E}{\Delta N}\right)

where ΔE=E2E1\Delta E = E_2 - E_1 and ΔN=N2N1\Delta N = N_2 - N_1.

Given:

  • Point 1: N1=10123.56N_1 = 10123.56, E1=10156.92E_1 = 10156.92
  • Point 2: N2=9905.56N_2 = 9905.56, E2=9923.57E_2 = 9923.57

ΔN=9905.5610123.56=218.00\Delta N = 9905.56 - 10123.56 = -218.00 ΔE=9923.5710156.92=233.35\Delta E = 9923.57 - 10156.92 = -233.35

Azimuth=arctan(233.35218.00)\text{Azimuth} = \arctan\left(\frac{-233.35}{-218.00}\right)

Now, let's calculate this value.

Azimuth=arctan(1.0704)\text{Azimuth} = \arctan\left(1.0704\right) Azimuth47.73\text{Azimuth} \approx 47.73^\circ

Since both ΔE\Delta E and ΔN\Delta N are negative, the direction is in the third quadrant, so we add 180° to get the correct azimuth:

Azimuth from Point 1 to Point 2=227.73\text{Azimuth from Point 1 to Point 2} = 227.73^\circ

Step 2: Adjust the Azimuth by the Given Angle

Next, we add the clockwise horizontal angle (312° 46' 23'') to the azimuth we just calculated.

New Azimuth=227.73+312.773\text{New Azimuth} = 227.73^\circ + 312.773^\circ

New Azimuth=540.503\text{New Azimuth} = 540.503^\circ

Since azimuths are generally given in the range of 0° to 360°, subtract 360°:

New Azimuth=540.503360=180.503\text{New Azimuth} = 540.503^\circ - 360^\circ = 180.503^\circ

Step 3: Compute the New Coordinates

Now that we have the azimuth and the distance, we can compute the new coordinates using:

ΔN=d×cos(New Azimuth)\Delta N' = d \times \cos(\text{New Azimuth}) ΔE=d×sin(New Azimuth)\Delta E' = d \times \sin(\text{New Azimuth})

where d=309.92d = 309.92 ft, and the new azimuth is 180.503°.

Let's calculate ΔN\Delta N' and ΔE\Delta E':

ΔN=309.92×cos(180.503)\Delta N' = 309.92 \times \cos(180.503^\circ) ΔE=309.92×sin(180.503)\Delta E' = 309.92 \times \sin(180.503^\circ)

Calculate the New Coordinates

Finally, add these to the coordinates of Point 1:

Nnew=N1+ΔNN_{\text{new}} = N_1 + \Delta N' Enew=E1+ΔEE_{\text{new}} = E_1 + \Delta E'

Let’s perform the final calculations for ΔN\Delta N' and ΔE\Delta E'.The coordinates of the new point, located 309.92 feet from Point 1 at a clockwise horizontal angle of 312° 46' 23" from the line connecting Point 1 and Point 2, are approximately:

  • Northing (N): 9813.65
  • Easting (E): 10154.20

Would you like further details or have any questions about the solution?

Related Questions:

  1. How would the calculation change if the distance was in meters instead of feet?
  2. What if the angle was counterclockwise instead of clockwise?
  3. How can you compute the inverse direction, i.e., from the new point back to Point 1?
  4. How would the azimuth calculation differ if the points were in a different quadrant?
  5. How can you perform similar calculations using software like AutoCAD or GIS tools?

Tip:

Always double-check your azimuth adjustments, especially when working across different quadrants or when the sum exceeds 360°.

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Math Problem Analysis

Mathematical Concepts

Coordinate Geometry
Azimuth Calculation
Trigonometry

Formulas

Azimuth = arctan(ΔE / ΔN)
New Coordinates: ΔN' = d × cos(New Azimuth), ΔE' = d × sin(New Azimuth)

Theorems

Trigonometric Functions for Coordinate Transformation

Suitable Grade Level

Grades 10-12