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Finding the Fourth Proportional to 664.90, 997.35 and 421.70

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Solution

The fourth proportional to 664.90, 997.35 and 421.70 is: 632.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    664.90 : 997.35 = 421.70 : x
  2. Step 2: Convert to fraction form
    664.90/997.35 = 421.70/x
  3. Step 3: Cross multiply
    664.90x = 997.35 × 421.70
  4. Step 4: Simplify right side
    664.90x = 420,582.50
  5. Step 5: Solve for x
    x = 420,582.50/664.90
  6. Step 6: Final answer
    x = 632.55

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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.