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Finding the Fourth Proportional to 478.64, 660.12 and 391.16

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Solution

The fourth proportional to 478.64, 660.12 and 391.16 is: 539.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    478.64 : 660.12 = 391.16 : x
  2. Step 2: Convert to fraction form
    478.64/660.12 = 391.16/x
  3. Step 3: Cross multiply
    478.64x = 660.12 × 391.16
  4. Step 4: Simplify right side
    478.64x = 258,212.54
  5. Step 5: Solve for x
    x = 258,212.54/478.64
  6. Step 6: Final answer
    x = 539.47

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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.