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Finding the Fourth Proportional to 1,270.40, 1,905 and 404.72

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Solution

The fourth proportional to 1,270.40, 1,905 and 404.72 is: 606.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,270.40 : 1,905 = 404.72 : x
  2. Step 2: Convert to fraction form
    1,270.40/1,905 = 404.72/x
  3. Step 3: Cross multiply
    1,270.40x = 1,905 × 404.72
  4. Step 4: Simplify right side
    1,270.40x = 770,991.60
  5. Step 5: Solve for x
    x = 770,991.60/1,270.40
  6. Step 6: Final answer
    x = 606.89

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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.