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Finding the Fourth Proportional to 670.38, 1,005.90 and 259.80

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Solution

The fourth proportional to 670.38, 1,005.90 and 259.80 is: 389.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    670.38 : 1,005.90 = 259.80 : x
  2. Step 2: Convert to fraction form
    670.38/1,005.90 = 259.80/x
  3. Step 3: Cross multiply
    670.38x = 1,005.90 × 259.80
  4. Step 4: Simplify right side
    670.38x = 261,327.79
  5. Step 5: Solve for x
    x = 261,327.79/670.38
  6. Step 6: Final answer
    x = 389.82

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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.