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Finding the Fourth Proportional to 1,223.28, 1,687.92 and 699.20

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Solution

The fourth proportional to 1,223.28, 1,687.92 and 699.20 is: 964.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,223.28 : 1,687.92 = 699.20 : x
  2. Step 2: Convert to fraction form
    1,223.28/1,687.92 = 699.20/x
  3. Step 3: Cross multiply
    1,223.28x = 1,687.92 × 699.20
  4. Step 4: Simplify right side
    1,223.28x = 1,180,193.66
  5. Step 5: Solve for x
    x = 1,180,193.66/1,223.28
  6. Step 6: Final answer
    x = 964.78

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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.