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Finding the Fourth Proportional to 442.90, 664.80 and 391.87

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Solution

The fourth proportional to 442.90, 664.80 and 391.87 is: 588.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    442.90 : 664.80 = 391.87 : x
  2. Step 2: Convert to fraction form
    442.90/664.80 = 391.87/x
  3. Step 3: Cross multiply
    442.90x = 664.80 × 391.87
  4. Step 4: Simplify right side
    442.90x = 260,515.18
  5. Step 5: Solve for x
    x = 260,515.18/442.90
  6. Step 6: Final answer
    x = 588.20

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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.