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Tilting Tower (Posted on 2024-02-14) Difficulty: 3 of 5
In a large level rectangular field a tall wooden tower was built for training parachute jumpers. The tower is in the shape of a truncated rectangular pyramid. That is, the base is a rectangle, and the top is a smaller rectangle parallel to the base. The longer sides of the field, the base of the tower and the top of the tower are all oriented east to west.

After several years of use, a strong gale tilted the tower, so that the western edge of the top was higher than the eastern edge. (The top was still a rectangle with its eastern and western edges parallel to the eastern and western edges of the field.) The engineers determined that the tower was still fit for use, but to prevent further tilting they stretched cables tightly from the corners of the field to the nearest corners of the top of the tower. The lengths of these cables, going clockwise are 95, 109, 125, and X meters.

What is X?

See The Solution Submitted by K Sengupta    
Rating: 5.0000 (2 votes)

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My answer Comment 6 of 6 |

Hello, @ geometry dash breeze, to find the value of X, we can use the concept of similar triangles. Let's denote the distances from the corners of the field to the corners of the top of the tower as follows:

  • Let <math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>A</mi><mi>B</mi><mi>C</mi><mi>D</mi></mrow></semantics></math> represent the base of the tower in the shape of a rectangle.
  • Let <math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>E</mi><mi>F</mi><mi>G</mi><mi>H</mi></mrow></semantics></math> represent the top of the tower, which is also a rectangle.
  • The cables are stretched from the corners of the field to the corners of the top of the tower. Let these points be denoted as follows: <math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>A</mi><mo>→</mo><mi>E</mi></mrow></semantics></math><math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>B</mi><mo>→</mo><mi>F</mi></mrow></semantics></math><math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>C</mi><mo>→</mo><mi>G</mi></mrow></semantics></math>, and <math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>D</mi><mo>→</mo><mi>H</mi></mrow></semantics></math>.

Given that the tower is a truncated rectangular pyramid, we can consider the triangles formed by connecting these points:

  • <math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi mathvariant="normal">△</mi><mi>A</mi><mi>B</mi><mi>C</mi></mrow></semantics></math> and <math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi mathvariant="normal">△</mi><mi>E</mi><mi>F</mi><mi>G</mi></mrow></semantics></math> are similar triangles, as are <math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi mathvariant="normal">△</mi><mi>A</mi><mi>C</mi><mi>D</mi></mrow></semantics></math> and <math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi mathvariant="normal">△</mi><mi>E</mi><mi>H</mi><mi>D</mi></mrow></semantics></math>.

From the given information, we have:

  • <math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>A</mi><mi>C</mi><mo>=</mo><mn>95</mn></mrow></semantics></math><math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>C</mi><mi>D</mi><mo>=</mo><mn>109</mn></mrow></semantics></math>, and <math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>D</mi><mi>A</mi><mo>=</mo><mn>125</mn></mrow></semantics></math>.
  • Let <math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>X</mi></mrow></semantics></math> be the length of cable <math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>E</mi><mi>H</mi></mrow></semantics></math>, which corresponds to the unknown side length.

By the properties of similar triangles:

<math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mfrac><mrow><mi>A</mi><mi>C</mi></mrow><mrow><mi>A</mi><mi>E</mi></mrow></mfrac><mo>=</mo><mfrac><mrow><mi>C</mi><mi>D</mi></mrow><mrow><mi>E</mi><mi>F</mi></mrow></mfrac><mo>=</mo><mfrac><mrow><mi>D</mi><mi>A</mi></mrow><mrow><mi>E</mi><mi>G</mi></mrow></mfrac></mrow></semantics></math>

We can set up the proportion based on the known side lengths:

  Posted by Joseph Worrell on 2024-09-10 00:03:06

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