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Finding the Fourth Proportional to 687.70, 948.87 and 392.95

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Solution

The fourth proportional to 687.70, 948.87 and 392.95 is: 542.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    687.70 : 948.87 = 392.95 : x
  2. Step 2: Convert to fraction form
    687.70/948.87 = 392.95/x
  3. Step 3: Cross multiply
    687.70x = 948.87 × 392.95
  4. Step 4: Simplify right side
    687.70x = 372,858.47
  5. Step 5: Solve for x
    x = 372,858.47/687.70
  6. Step 6: Final answer
    x = 542.18

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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.