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Finding the Fourth Proportional to 663.20, 915.07 and 401.21

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Solution

The fourth proportional to 663.20, 915.07 and 401.21 is: 553.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    663.20 : 915.07 = 401.21 : x
  2. Step 2: Convert to fraction form
    663.20/915.07 = 401.21/x
  3. Step 3: Cross multiply
    663.20x = 915.07 × 401.21
  4. Step 4: Simplify right side
    663.20x = 367,135.23
  5. Step 5: Solve for x
    x = 367,135.23/663.20
  6. Step 6: Final answer
    x = 553.58

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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.