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Finding the Fourth Proportional to 840.47, 1,261.44 and 429.89

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Solution

The fourth proportional to 840.47, 1,261.44 and 429.89 is: 645.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    840.47 : 1,261.44 = 429.89 : x
  2. Step 2: Convert to fraction form
    840.47/1,261.44 = 429.89/x
  3. Step 3: Cross multiply
    840.47x = 1,261.44 × 429.89
  4. Step 4: Simplify right side
    840.47x = 542,274.13
  5. Step 5: Solve for x
    x = 542,274.13/840.47
  6. Step 6: Final answer
    x = 645.21

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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.