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Finding the Fourth Proportional to 787.60, 1,085.78 and 492.68

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Solution

The fourth proportional to 787.60, 1,085.78 and 492.68 is: 679.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    787.60 : 1,085.78 = 492.68 : x
  2. Step 2: Convert to fraction form
    787.60/1,085.78 = 492.68/x
  3. Step 3: Cross multiply
    787.60x = 1,085.78 × 492.68
  4. Step 4: Simplify right side
    787.60x = 534,942.09
  5. Step 5: Solve for x
    x = 534,942.09/787.60
  6. Step 6: Final answer
    x = 679.21

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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.