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Finding the Fourth Proportional to 664.51, 916.78 and 398.85

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Solution

The fourth proportional to 664.51, 916.78 and 398.85 is: 550.27

Step by Step Solution

  1. Step 1: Write the proportion equation
    664.51 : 916.78 = 398.85 : x
  2. Step 2: Convert to fraction form
    664.51/916.78 = 398.85/x
  3. Step 3: Cross multiply
    664.51x = 916.78 × 398.85
  4. Step 4: Simplify right side
    664.51x = 365,656.78
  5. Step 5: Solve for x
    x = 365,656.78/664.51
  6. Step 6: Final answer
    x = 550.27

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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.