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Finding the Fourth Proportional to 645.92, 891.36 and 409.85

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Solution

The fourth proportional to 645.92, 891.36 and 409.85 is: 565.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    645.92 : 891.36 = 409.85 : x
  2. Step 2: Convert to fraction form
    645.92/891.36 = 409.85/x
  3. Step 3: Cross multiply
    645.92x = 891.36 × 409.85
  4. Step 4: Simplify right side
    645.92x = 365,319.44
  5. Step 5: Solve for x
    x = 365,319.44/645.92
  6. Step 6: Final answer
    x = 565.58

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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.