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Finding the Fourth Proportional to 997.78, 1,376.30 and 787.90

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Solution

The fourth proportional to 997.78, 1,376.30 and 787.90 is: 1,086.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    997.78 : 1,376.30 = 787.90 : x
  2. Step 2: Convert to fraction form
    997.78/1,376.30 = 787.90/x
  3. Step 3: Cross multiply
    997.78x = 1,376.30 × 787.90
  4. Step 4: Simplify right side
    997.78x = 1,084,386.77
  5. Step 5: Solve for x
    x = 1,084,386.77/997.78
  6. Step 6: Final answer
    x = 1,086.80

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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.