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Finding the Fourth Proportional to 1,123.70, 1,686.55 and 660.90

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Solution

The fourth proportional to 1,123.70, 1,686.55 and 660.90 is: 991.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,123.70 : 1,686.55 = 660.90 : x
  2. Step 2: Convert to fraction form
    1,123.70/1,686.55 = 660.90/x
  3. Step 3: Cross multiply
    1,123.70x = 1,686.55 × 660.90
  4. Step 4: Simplify right side
    1,123.70x = 1,114,640.90
  5. Step 5: Solve for x
    x = 1,114,640.90/1,123.70
  6. Step 6: Final answer
    x = 991.94

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.