Math Problem Statement

find the measure for ED and identify the formula or property used to get the answer

find the measure for ED and identify the formula or property used to get the answer

Solution

To find the measure of segment EDED, we need to analyze the geometric configuration. Here's how we can approach this:

Observations from the image:

  • Triangle ABCABC is a right triangle with AB=3AB = 3 and BC=4BC = 4. Using the Pythagorean theorem, ACAC can be calculated as: AC=AB2+BC2=32+42=5.AC = \sqrt{AB^2 + BC^2} = \sqrt{3^2 + 4^2} = 5. This is confirmed as AC=5AC = 5 is shown in the diagram.
  • ADAD is perpendicular to BCBC (forming a rectangle ABDCABDC), and its length AD=3.1623AD = 3.1623 is given.
  • Segment EDED forms part of a triangle ADEADE, where:
    • EDA=38.8845\angle EDA = 38.8845^\circ
    • EA=7.8102EA = 7.8102 (distance from EE to AA).

To find EDED, we can use the Law of Cosines in triangle ADEADE: ED2=EA2+AD22(EA)(AD)cos(EDA).ED^2 = EA^2 + AD^2 - 2(EA)(AD)\cos(\angle EDA).

Calculation:

  1. Substitute known values:

    • EA=7.8102EA = 7.8102,
    • AD=3.1623AD = 3.1623,
    • cos(EDA)=cos(38.8845)\cos(\angle EDA) = \cos(38.8845^\circ).
  2. Apply the formula: ED2=7.81022+3.162322(7.8102)(3.1623)cos(38.8845).ED^2 = 7.8102^2 + 3.1623^2 - 2(7.8102)(3.1623)\cos(38.8845^\circ).

  3. Simplify:

    • 7.81022=60.9897.8102^2 = 60.989,
    • 3.16232=10.0003.1623^2 = 10.000,
    • cos(38.8845)0.7809\cos(38.8845^\circ) \approx 0.7809,
    • 2(7.8102)(3.1623)cos(38.8845)38.3922(7.8102)(3.1623)\cos(38.8845^\circ) \approx 38.392.

Thus: ED2=60.989+10.00038.392=32.597.ED^2 = 60.989 + 10.000 - 38.392 = 32.597.

  1. Take the square root: ED=32.5975.71.ED = \sqrt{32.597} \approx 5.71.

Final Answer:

The length of EDED is approximately 5.71 units.

Formula/Property Used:

The Law of Cosines: c2=a2+b22abcos(C),c^2 = a^2 + b^2 - 2ab\cos(C), where a,ba, b are two sides, cc is the third side, and CC is the included angle.


Would you like further clarification or a breakdown of any step?

Expanding Questions:

  1. How can we confirm this result using trigonometry or another method?
  2. What are the properties of triangle ADEADE based on these dimensions?
  3. How does the Pythagorean theorem apply to other parts of this figure?
  4. Could this problem be approached using vector analysis?
  5. Can you find another segment of the diagram using similar methods?

Tip:

Always double-check cosine or trigonometric values for accuracy when solving geometry problems involving angles.

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Math Problem Analysis

Mathematical Concepts

Geometry
Trigonometry
Law of Cosines

Formulas

Law of Cosines: c^2 = a^2 + b^2 - 2ab cos(C)

Theorems

Law of Cosines

Suitable Grade Level

Grades 10-12