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Finding the Fourth Proportional to 781.74, 1,174.41 and 645.30

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Solution

The fourth proportional to 781.74, 1,174.41 and 645.30 is: 969.44

Step by Step Solution

  1. Step 1: Write the proportion equation
    781.74 : 1,174.41 = 645.30 : x
  2. Step 2: Convert to fraction form
    781.74/1,174.41 = 645.30/x
  3. Step 3: Cross multiply
    781.74x = 1,174.41 × 645.30
  4. Step 4: Simplify right side
    781.74x = 757,846.77
  5. Step 5: Solve for x
    x = 757,846.77/781.74
  6. Step 6: Final answer
    x = 969.44

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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.