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Finding the Fourth Proportional to 668.13, 1,000.75 and 420.49

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Solution

The fourth proportional to 668.13, 1,000.75 and 420.49 is: 629.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    668.13 : 1,000.75 = 420.49 : x
  2. Step 2: Convert to fraction form
    668.13/1,000.75 = 420.49/x
  3. Step 3: Cross multiply
    668.13x = 1,000.75 × 420.49
  4. Step 4: Simplify right side
    668.13x = 420,805.37
  5. Step 5: Solve for x
    x = 420,805.37/668.13
  6. Step 6: Final answer
    x = 629.83

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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.