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Finding the Fourth Proportional to 748.50, 1,121.70 and 285.78

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Solution

The fourth proportional to 748.50, 1,121.70 and 285.78 is: 428.27

Step by Step Solution

  1. Step 1: Write the proportion equation
    748.50 : 1,121.70 = 285.78 : x
  2. Step 2: Convert to fraction form
    748.50/1,121.70 = 285.78/x
  3. Step 3: Cross multiply
    748.50x = 1,121.70 × 285.78
  4. Step 4: Simplify right side
    748.50x = 320,559.43
  5. Step 5: Solve for x
    x = 320,559.43/748.50
  6. Step 6: Final answer
    x = 428.27

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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.