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Finding the Fourth Proportional to 687.40, 948.62 and 392.76

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Solution

The fourth proportional to 687.40, 948.62 and 392.76 is: 542.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    687.40 : 948.62 = 392.76 : x
  2. Step 2: Convert to fraction form
    687.40/948.62 = 392.76/x
  3. Step 3: Cross multiply
    687.40x = 948.62 × 392.76
  4. Step 4: Simplify right side
    687.40x = 372,580.97
  5. Step 5: Solve for x
    x = 372,580.97/687.40
  6. Step 6: Final answer
    x = 542.02

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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.