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Finding the Fourth Proportional to 721.91, 1,086.75 and 654.86

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Solution

The fourth proportional to 721.91, 1,086.75 and 654.86 is: 985.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    721.91 : 1,086.75 = 654.86 : x
  2. Step 2: Convert to fraction form
    721.91/1,086.75 = 654.86/x
  3. Step 3: Cross multiply
    721.91x = 1,086.75 × 654.86
  4. Step 4: Simplify right side
    721.91x = 711,669.11
  5. Step 5: Solve for x
    x = 711,669.11/721.91
  6. Step 6: Final answer
    x = 985.81

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.