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Finding the Fourth Proportional to 615.40, 921.88 and 408.85

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Solution

The fourth proportional to 615.40, 921.88 and 408.85 is: 612.46

Step by Step Solution

  1. Step 1: Write the proportion equation
    615.40 : 921.88 = 408.85 : x
  2. Step 2: Convert to fraction form
    615.40/921.88 = 408.85/x
  3. Step 3: Cross multiply
    615.40x = 921.88 × 408.85
  4. Step 4: Simplify right side
    615.40x = 376,908.84
  5. Step 5: Solve for x
    x = 376,908.84/615.40
  6. Step 6: Final answer
    x = 612.46

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.