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Finding the Fourth Proportional to 781.04, 1,172.36 and 391.32

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Solution

The fourth proportional to 781.04, 1,172.36 and 391.32 is: 587.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    781.04 : 1,172.36 = 391.32 : x
  2. Step 2: Convert to fraction form
    781.04/1,172.36 = 391.32/x
  3. Step 3: Cross multiply
    781.04x = 1,172.36 × 391.32
  4. Step 4: Simplify right side
    781.04x = 458,765.96
  5. Step 5: Solve for x
    x = 458,765.96/781.04
  6. Step 6: Final answer
    x = 587.38

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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.