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Finding the Fourth Proportional to 478.31, 660.26 and 312.66

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Solution

The fourth proportional to 478.31, 660.26 and 312.66 is: 431.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    478.31 : 660.26 = 312.66 : x
  2. Step 2: Convert to fraction form
    478.31/660.26 = 312.66/x
  3. Step 3: Cross multiply
    478.31x = 660.26 × 312.66
  4. Step 4: Simplify right side
    478.31x = 206,437.67
  5. Step 5: Solve for x
    x = 206,437.67/478.31
  6. Step 6: Final answer
    x = 431.60

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.