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Finding the Fourth Proportional to 753.70, 1,129.20 and 645.70

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Solution

The fourth proportional to 753.70, 1,129.20 and 645.70 is: 967.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    753.70 : 1,129.20 = 645.70 : x
  2. Step 2: Convert to fraction form
    753.70/1,129.20 = 645.70/x
  3. Step 3: Cross multiply
    753.70x = 1,129.20 × 645.70
  4. Step 4: Simplify right side
    753.70x = 729,124.44
  5. Step 5: Solve for x
    x = 729,124.44/753.70
  6. Step 6: Final answer
    x = 967.39

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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.