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Finding the Fourth Proportional to 661.45, 912.17 and 395.85

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Solution

The fourth proportional to 661.45, 912.17 and 395.85 is: 545.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    661.45 : 912.17 = 395.85 : x
  2. Step 2: Convert to fraction form
    661.45/912.17 = 395.85/x
  3. Step 3: Cross multiply
    661.45x = 912.17 × 395.85
  4. Step 4: Simplify right side
    661.45x = 361,083.48
  5. Step 5: Solve for x
    x = 361,083.48/661.45
  6. Step 6: Final answer
    x = 545.90

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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.