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Finding the Fourth Proportional to 747.81, 1,120.68 and 644.40

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Solution

The fourth proportional to 747.81, 1,120.68 and 644.40 is: 965.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    747.81 : 1,120.68 = 644.40 : x
  2. Step 2: Convert to fraction form
    747.81/1,120.68 = 644.40/x
  3. Step 3: Cross multiply
    747.81x = 1,120.68 × 644.40
  4. Step 4: Simplify right side
    747.81x = 722,166.19
  5. Step 5: Solve for x
    x = 722,166.19/747.81
  6. Step 6: Final answer
    x = 965.71

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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.