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Finding the Fourth Proportional to 645.11, 890.39 and 409.38

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Solution

The fourth proportional to 645.11, 890.39 and 409.38 is: 565.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    645.11 : 890.39 = 409.38 : x
  2. Step 2: Convert to fraction form
    645.11/890.39 = 409.38/x
  3. Step 3: Cross multiply
    645.11x = 890.39 × 409.38
  4. Step 4: Simplify right side
    645.11x = 364,511.80
  5. Step 5: Solve for x
    x = 364,511.80/645.11
  6. Step 6: Final answer
    x = 565.04

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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.