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Finding the Fourth Proportional to 947.31, 1,420.35 and 426.76

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Solution

The fourth proportional to 947.31, 1,420.35 and 426.76 is: 639.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    947.31 : 1,420.35 = 426.76 : x
  2. Step 2: Convert to fraction form
    947.31/1,420.35 = 426.76/x
  3. Step 3: Cross multiply
    947.31x = 1,420.35 × 426.76
  4. Step 4: Simplify right side
    947.31x = 606,143.41
  5. Step 5: Solve for x
    x = 606,143.41/947.31
  6. Step 6: Final answer
    x = 639.86

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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.