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Finding the Fourth Proportional to 420.86, 631.70 and 321.70

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Solution

The fourth proportional to 420.86, 631.70 and 321.70 is: 482.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.86 : 631.70 = 321.70 : x
  2. Step 2: Convert to fraction form
    420.86/631.70 = 321.70/x
  3. Step 3: Cross multiply
    420.86x = 631.70 × 321.70
  4. Step 4: Simplify right side
    420.86x = 203,217.89
  5. Step 5: Solve for x
    x = 203,217.89/420.86
  6. Step 6: Final answer
    x = 482.86

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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.