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Finding the Fourth Proportional to 663.56, 915.40 and 397.88

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Solution

The fourth proportional to 663.56, 915.40 and 397.88 is: 548.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    663.56 : 915.40 = 397.88 : x
  2. Step 2: Convert to fraction form
    663.56/915.40 = 397.88/x
  3. Step 3: Cross multiply
    663.56x = 915.40 × 397.88
  4. Step 4: Simplify right side
    663.56x = 364,218.71
  5. Step 5: Solve for x
    x = 364,218.71/663.56
  6. Step 6: Final answer
    x = 548.89

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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.