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Finding the Fourth Proportional to 645.48, 890.74 and 449

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Solution

The fourth proportional to 645.48, 890.74 and 449 is: 619.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    645.48 : 890.74 = 449 : x
  2. Step 2: Convert to fraction form
    645.48/890.74 = 449/x
  3. Step 3: Cross multiply
    645.48x = 890.74 × 449
  4. Step 4: Simplify right side
    645.48x = 399,942.26
  5. Step 5: Solve for x
    x = 399,942.26/645.48
  6. Step 6: Final answer
    x = 619.60

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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.