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Finding the Fourth Proportional to 687.31, 948.65 and 392.75

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Solution

The fourth proportional to 687.31, 948.65 and 392.75 is: 542.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    687.31 : 948.65 = 392.75 : x
  2. Step 2: Convert to fraction form
    687.31/948.65 = 392.75/x
  3. Step 3: Cross multiply
    687.31x = 948.65 × 392.75
  4. Step 4: Simplify right side
    687.31x = 372,577.05
  5. Step 5: Solve for x
    x = 372,577.05/687.31
  6. Step 6: Final answer
    x = 542.08

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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.