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Finding the Fourth Proportional to 781.45, 1,171.09 and 646.12

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Solution

The fourth proportional to 781.45, 1,171.09 and 646.12 is: 968.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    781.45 : 1,171.09 = 646.12 : x
  2. Step 2: Convert to fraction form
    781.45/1,171.09 = 646.12/x
  3. Step 3: Cross multiply
    781.45x = 1,171.09 × 646.12
  4. Step 4: Simplify right side
    781.45x = 756,661.44
  5. Step 5: Solve for x
    x = 756,661.44/781.45
  6. Step 6: Final answer
    x = 968.28

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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.