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Finding the Fourth Proportional to 840.89, 1,261.61 and 429.91

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Solution

The fourth proportional to 840.89, 1,261.61 and 429.91 is: 645.01

Step by Step Solution

  1. Step 1: Write the proportion equation
    840.89 : 1,261.61 = 429.91 : x
  2. Step 2: Convert to fraction form
    840.89/1,261.61 = 429.91/x
  3. Step 3: Cross multiply
    840.89x = 1,261.61 × 429.91
  4. Step 4: Simplify right side
    840.89x = 542,384.58
  5. Step 5: Solve for x
    x = 542,384.58/840.89
  6. Step 6: Final answer
    x = 645.01

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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.