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Finding the Fourth Proportional to 429.28, 640.26 and 392.84

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Solution

The fourth proportional to 429.28, 640.26 and 392.84 is: 585.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    429.28 : 640.26 = 392.84 : x
  2. Step 2: Convert to fraction form
    429.28/640.26 = 392.84/x
  3. Step 3: Cross multiply
    429.28x = 640.26 × 392.84
  4. Step 4: Simplify right side
    429.28x = 251,519.74
  5. Step 5: Solve for x
    x = 251,519.74/429.28
  6. Step 6: Final answer
    x = 585.91

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.