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Finding the Fourth Proportional to 749.21, 1,123.89 and 287.38

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Solution

The fourth proportional to 749.21, 1,123.89 and 287.38 is: 431.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    749.21 : 1,123.89 = 287.38 : x
  2. Step 2: Convert to fraction form
    749.21/1,123.89 = 287.38/x
  3. Step 3: Cross multiply
    749.21x = 1,123.89 × 287.38
  4. Step 4: Simplify right side
    749.21x = 322,977.17
  5. Step 5: Solve for x
    x = 322,977.17/749.21
  6. Step 6: Final answer
    x = 431.09

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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.