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Finding the Fourth Proportional to 1,221.87, 1,686.27 and 697.89

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Solution

The fourth proportional to 1,221.87, 1,686.27 and 697.89 is: 963.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,221.87 : 1,686.27 = 697.89 : x
  2. Step 2: Convert to fraction form
    1,221.87/1,686.27 = 697.89/x
  3. Step 3: Cross multiply
    1,221.87x = 1,686.27 × 697.89
  4. Step 4: Simplify right side
    1,221.87x = 1,176,830.97
  5. Step 5: Solve for x
    x = 1,176,830.97/1,221.87
  6. Step 6: Final answer
    x = 963.14

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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.