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Finding the Fourth Proportional to 787.61, 1,086.19 and 492.90

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Solution

The fourth proportional to 787.61, 1,086.19 and 492.90 is: 679.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    787.61 : 1,086.19 = 492.90 : x
  2. Step 2: Convert to fraction form
    787.61/1,086.19 = 492.90/x
  3. Step 3: Cross multiply
    787.61x = 1,086.19 × 492.90
  4. Step 4: Simplify right side
    787.61x = 535,381.82
  5. Step 5: Solve for x
    x = 535,381.82/787.61
  6. Step 6: Final answer
    x = 679.76

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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.