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Finding the Fourth Proportional to 1,272.62, 1,909.12 and 407

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Solution

The fourth proportional to 1,272.62, 1,909.12 and 407 is: 610.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,272.62 : 1,909.12 = 407 : x
  2. Step 2: Convert to fraction form
    1,272.62/1,909.12 = 407/x
  3. Step 3: Cross multiply
    1,272.62x = 1,909.12 × 407
  4. Step 4: Simplify right side
    1,272.62x = 777,011.84
  5. Step 5: Solve for x
    x = 777,011.84/1,272.62
  6. Step 6: Final answer
    x = 610.56

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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.