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Finding the Fourth Proportional to 663.40, 915.18 and 397.67

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Solution

The fourth proportional to 663.40, 915.18 and 397.67 is: 548.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    663.40 : 915.18 = 397.67 : x
  2. Step 2: Convert to fraction form
    663.40/915.18 = 397.67/x
  3. Step 3: Cross multiply
    663.40x = 915.18 × 397.67
  4. Step 4: Simplify right side
    663.40x = 363,939.63
  5. Step 5: Solve for x
    x = 363,939.63/663.40
  6. Step 6: Final answer
    x = 548.60

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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.