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Finding the Fourth Proportional to 1,005.70, 1,387.78 and 612.65

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Solution

The fourth proportional to 1,005.70, 1,387.78 and 612.65 is: 845.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,005.70 : 1,387.78 = 612.65 : x
  2. Step 2: Convert to fraction form
    1,005.70/1,387.78 = 612.65/x
  3. Step 3: Cross multiply
    1,005.70x = 1,387.78 × 612.65
  4. Step 4: Simplify right side
    1,005.70x = 850,213.41
  5. Step 5: Solve for x
    x = 850,213.41/1,005.70
  6. Step 6: Final answer
    x = 845.39

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.