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Finding the Fourth Proportional to 660.78, 911.78 and 395.16

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Solution

The fourth proportional to 660.78, 911.78 and 395.16 is: 545.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    660.78 : 911.78 = 395.16 : x
  2. Step 2: Convert to fraction form
    660.78/911.78 = 395.16/x
  3. Step 3: Cross multiply
    660.78x = 911.78 × 395.16
  4. Step 4: Simplify right side
    660.78x = 360,298.98
  5. Step 5: Solve for x
    x = 360,298.98/660.78
  6. Step 6: Final answer
    x = 545.26

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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.