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Finding the Fourth Proportional to 781.59, 1,172.49 and 391.62

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Solution

The fourth proportional to 781.59, 1,172.49 and 391.62 is: 587.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    781.59 : 1,172.49 = 391.62 : x
  2. Step 2: Convert to fraction form
    781.59/1,172.49 = 391.62/x
  3. Step 3: Cross multiply
    781.59x = 1,172.49 × 391.62
  4. Step 4: Simplify right side
    781.59x = 459,170.53
  5. Step 5: Solve for x
    x = 459,170.53/781.59
  6. Step 6: Final answer
    x = 587.48

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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.