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Finding the Fourth Proportional to 814.60, 1,219.74 and 428.68

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Solution

The fourth proportional to 814.60, 1,219.74 and 428.68 is: 641.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    814.60 : 1,219.74 = 428.68 : x
  2. Step 2: Convert to fraction form
    814.60/1,219.74 = 428.68/x
  3. Step 3: Cross multiply
    814.60x = 1,219.74 × 428.68
  4. Step 4: Simplify right side
    814.60x = 522,878.14
  5. Step 5: Solve for x
    x = 522,878.14/814.60
  6. Step 6: Final answer
    x = 641.88

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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.