Math Problem Statement

In the right triangle ABC shown, E and D are the trisection points of the hypotenuse AB. If CD = 7 and CE = 6, what is the length of hypotenuse AB?

Solution

To solve this problem, we can use the information about points DD and EE being trisection points on the hypotenuse ABAB and apply the Pythagorean theorem with a coordinate-based approach.

Let's proceed with the following steps:

  1. Assign coordinates to points:

    • Let AA be at the origin (0,0)(0, 0).
    • Let BB be at (x,y)(x, y).
    • Since DD and EE are trisection points, we can place DD at (x3,y3)\left(\frac{x}{3}, \frac{y}{3}\right) and EE at (2x3,2y3)\left(\frac{2x}{3}, \frac{2y}{3}\right).
  2. Calculate lengths CDCD and CECE:

    • We know CD=7CD = 7 and CE=6CE = 6.
    • Using the distance formula, we can set up equations for each segment.

    For CDCD: CD=(x30)2+(y3y)2=7CD = \sqrt{\left(\frac{x}{3} - 0\right)^2 + \left(\frac{y}{3} - y\right)^2} = 7 Simplifying, we get: (x3)2+(2y3)2=7\sqrt{\left(\frac{x}{3}\right)^2 + \left(\frac{-2y}{3}\right)^2} = 7 x29+4y29=7\sqrt{\frac{x^2}{9} + \frac{4y^2}{9}} = 7 Squaring both sides: x2+4y29=49\frac{x^2 + 4y^2}{9} = 49 x2+4y2=441x^2 + 4y^2 = 441

    For CECE: CE=(2x30)2+(2y3y)2=6CE = \sqrt{\left(\frac{2x}{3} - 0\right)^2 + \left(\frac{2y}{3} - y\right)^2} = 6 Simplifying, we get: (2x3)2+(y3)2=6\sqrt{\left(\frac{2x}{3}\right)^2 + \left(\frac{-y}{3}\right)^2} = 6 4x29+y29=6\sqrt{\frac{4x^2}{9} + \frac{y^2}{9}} = 6 Squaring both sides: 4x2+y29=36\frac{4x^2 + y^2}{9} = 36 4x2+y2=3244x^2 + y^2 = 324

  3. Solve the system of equations: We now have two equations: x2+4y2=441x^2 + 4y^2 = 441 4x2+y2=3244x^2 + y^2 = 324

    To eliminate one variable, we can multiply the first equation by 4: 4x2+16y2=17644x^2 + 16y^2 = 1764 Now, subtract the second equation: (4x2+16y2)(4x2+y2)=1764324(4x^2 + 16y^2) - (4x^2 + y^2) = 1764 - 324 15y2=144015y^2 = 1440 y2=96y^2 = 96 y=96=46y = \sqrt{96} = 4\sqrt{6}

    Substitute y=46y = 4\sqrt{6} into the first equation: x2+4(96)=441x^2 + 4(96) = 441 x2+384=441x^2 + 384 = 441 x2=57x^2 = 57 x=57x = \sqrt{57}

  4. Find the length of hypotenuse ABAB: The length of ABAB is: AB=x2+y2=57+96=153=317AB = \sqrt{x^2 + y^2} = \sqrt{57 + 96} = \sqrt{153} = 3\sqrt{17}

Thus, the length of the hypotenuse ABAB is 317\boxed{3\sqrt{17}}.

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


Here are 5 related questions to explore further:

  1. How does the trisection of a segment affect the coordinate locations of points?
  2. What other methods can solve a problem involving trisection points and distances?
  3. How would this change if the triangle was not a right triangle?
  4. Can this approach be applied if CD and CE were in different ratios?
  5. How does the Pythagorean theorem apply in coordinate-based proofs?

Tip: Remember to break complex problems down by assigning coordinates to key points and setting up equations systematically.

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Math Problem Analysis

Mathematical Concepts

Coordinate Geometry
Distance Formula
Pythagorean Theorem
System of Equations

Formulas

Distance formula: d = √((x2 - x1)^2 + (y2 - y1)^2)
System of equations
Pythagorean theorem: a^2 + b^2 = c^2

Theorems

Pythagorean Theorem

Suitable Grade Level

Grades 10-12