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Finding the Fourth Proportional to 478.70, 659.84 and 391.22

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Solution

The fourth proportional to 478.70, 659.84 and 391.22 is: 539.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    478.70 : 659.84 = 391.22 : x
  2. Step 2: Convert to fraction form
    478.70/659.84 = 391.22/x
  3. Step 3: Cross multiply
    478.70x = 659.84 × 391.22
  4. Step 4: Simplify right side
    478.70x = 258,142.60
  5. Step 5: Solve for x
    x = 258,142.60/478.70
  6. Step 6: Final answer
    x = 539.26

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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.