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Finding the Fourth Proportional to 429.25, 643.89 and 140.68

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Solution

The fourth proportional to 429.25, 643.89 and 140.68 is: 211.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    429.25 : 643.89 = 140.68 : x
  2. Step 2: Convert to fraction form
    429.25/643.89 = 140.68/x
  3. Step 3: Cross multiply
    429.25x = 643.89 × 140.68
  4. Step 4: Simplify right side
    429.25x = 90,582.45
  5. Step 5: Solve for x
    x = 90,582.45/429.25
  6. Step 6: Final answer
    x = 211.02

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.