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Finding the Fourth Proportional to 1,285.28, 1,773.26 and 787.40

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Solution

The fourth proportional to 1,285.28, 1,773.26 and 787.40 is: 1,086.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,285.28 : 1,773.26 = 787.40 : x
  2. Step 2: Convert to fraction form
    1,285.28/1,773.26 = 787.40/x
  3. Step 3: Cross multiply
    1,285.28x = 1,773.26 × 787.40
  4. Step 4: Simplify right side
    1,285.28x = 1,396,264.92
  5. Step 5: Solve for x
    x = 1,396,264.92/1,285.28
  6. Step 6: Final answer
    x = 1,086.35

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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.