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Finding the Fourth Proportional to 814.30, 1,221.45 and 619.90

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Solution

The fourth proportional to 814.30, 1,221.45 and 619.90 is: 929.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    814.30 : 1,221.45 = 619.90 : x
  2. Step 2: Convert to fraction form
    814.30/1,221.45 = 619.90/x
  3. Step 3: Cross multiply
    814.30x = 1,221.45 × 619.90
  4. Step 4: Simplify right side
    814.30x = 757,176.86
  5. Step 5: Solve for x
    x = 757,176.86/814.30
  6. Step 6: Final answer
    x = 929.85

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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.