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Finding the Fourth Proportional to 429.30, 639.90 and 411.08

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Solution

The fourth proportional to 429.30, 639.90 and 411.08 is: 612.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    429.30 : 639.90 = 411.08 : x
  2. Step 2: Convert to fraction form
    429.30/639.90 = 411.08/x
  3. Step 3: Cross multiply
    429.30x = 639.90 × 411.08
  4. Step 4: Simplify right side
    429.30x = 263,046.89
  5. Step 5: Solve for x
    x = 263,046.89/429.30
  6. Step 6: Final answer
    x = 612.73

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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.