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Finding the Fourth Proportional to 781.40, 1,171.18 and 434.21

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Solution

The fourth proportional to 781.40, 1,171.18 and 434.21 is: 650.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    781.40 : 1,171.18 = 434.21 : x
  2. Step 2: Convert to fraction form
    781.40/1,171.18 = 434.21/x
  3. Step 3: Cross multiply
    781.40x = 1,171.18 × 434.21
  4. Step 4: Simplify right side
    781.40x = 508,540.56
  5. Step 5: Solve for x
    x = 508,540.56/781.40
  6. Step 6: Final answer
    x = 650.81

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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.