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Finding the Fourth Proportional to 478.98, 660.38 and 390.15

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Solution

The fourth proportional to 478.98, 660.38 and 390.15 is: 537.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    478.98 : 660.38 = 390.15 : x
  2. Step 2: Convert to fraction form
    478.98/660.38 = 390.15/x
  3. Step 3: Cross multiply
    478.98x = 660.38 × 390.15
  4. Step 4: Simplify right side
    478.98x = 257,645.31
  5. Step 5: Solve for x
    x = 257,645.31/478.98
  6. Step 6: Final answer
    x = 537.90

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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.