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Finding the Fourth Proportional to 664.28, 916.61 and 398.64

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Solution

The fourth proportional to 664.28, 916.61 and 398.64 is: 550.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    664.28 : 916.61 = 398.64 : x
  2. Step 2: Convert to fraction form
    664.28/916.61 = 398.64/x
  3. Step 3: Cross multiply
    664.28x = 916.61 × 398.64
  4. Step 4: Simplify right side
    664.28x = 365,397.41
  5. Step 5: Solve for x
    x = 365,397.41/664.28
  6. Step 6: Final answer
    x = 550.07

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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.