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Finding the Fourth Proportional to 1,005.80, 1,388.10 and 612.86

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Solution

The fourth proportional to 1,005.80, 1,388.10 and 612.86 is: 845.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,005.80 : 1,388.10 = 612.86 : x
  2. Step 2: Convert to fraction form
    1,005.80/1,388.10 = 612.86/x
  3. Step 3: Cross multiply
    1,005.80x = 1,388.10 × 612.86
  4. Step 4: Simplify right side
    1,005.80x = 850,710.97
  5. Step 5: Solve for x
    x = 850,710.97/1,005.80
  6. Step 6: Final answer
    x = 845.81

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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.