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Finding the Fourth Proportional to 840.26, 1,260.40 and 429.40

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Solution

The fourth proportional to 840.26, 1,260.40 and 429.40 is: 644.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    840.26 : 1,260.40 = 429.40 : x
  2. Step 2: Convert to fraction form
    840.26/1,260.40 = 429.40/x
  3. Step 3: Cross multiply
    840.26x = 1,260.40 × 429.40
  4. Step 4: Simplify right side
    840.26x = 541,215.76
  5. Step 5: Solve for x
    x = 541,215.76/840.26
  6. Step 6: Final answer
    x = 644.11

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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.