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Finding the Fourth Proportional to 396.40, 546.49 and 278.21

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Solution

The fourth proportional to 396.40, 546.49 and 278.21 is: 383.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    396.40 : 546.49 = 278.21 : x
  2. Step 2: Convert to fraction form
    396.40/546.49 = 278.21/x
  3. Step 3: Cross multiply
    396.40x = 546.49 × 278.21
  4. Step 4: Simplify right side
    396.40x = 152,038.98
  5. Step 5: Solve for x
    x = 152,038.98/396.40
  6. Step 6: Final answer
    x = 383.55

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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.