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Finding the Fourth Proportional to 429.11, 643.65 and 140.55

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Solution

The fourth proportional to 429.11, 643.65 and 140.55 is: 210.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    429.11 : 643.65 = 140.55 : x
  2. Step 2: Convert to fraction form
    429.11/643.65 = 140.55/x
  3. Step 3: Cross multiply
    429.11x = 643.65 × 140.55
  4. Step 4: Simplify right side
    429.11x = 90,465.01
  5. Step 5: Solve for x
    x = 90,465.01/429.11
  6. Step 6: Final answer
    x = 210.82

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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.