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Finding the Fourth Proportional to 1,005.78, 1,388.02 and 557.64

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Solution

The fourth proportional to 1,005.78, 1,388.02 and 557.64 is: 769.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,005.78 : 1,388.02 = 557.64 : x
  2. Step 2: Convert to fraction form
    1,005.78/1,388.02 = 557.64/x
  3. Step 3: Cross multiply
    1,005.78x = 1,388.02 × 557.64
  4. Step 4: Simplify right side
    1,005.78x = 774,015.47
  5. Step 5: Solve for x
    x = 774,015.47/1,005.78
  6. Step 6: Final answer
    x = 769.57

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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.