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Finding the Fourth Proportional to 491.40, 677.82 and 393

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Solution

The fourth proportional to 491.40, 677.82 and 393 is: 542.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    491.40 : 677.82 = 393 : x
  2. Step 2: Convert to fraction form
    491.40/677.82 = 393/x
  3. Step 3: Cross multiply
    491.40x = 677.82 × 393
  4. Step 4: Simplify right side
    491.40x = 266,383.26
  5. Step 5: Solve for x
    x = 266,383.26/491.40
  6. Step 6: Final answer
    x = 542.09

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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.