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Finding the Fourth Proportional to 811.87, 1,218.11 and 487.47

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Solution

The fourth proportional to 811.87, 1,218.11 and 487.47 is: 731.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    811.87 : 1,218.11 = 487.47 : x
  2. Step 2: Convert to fraction form
    811.87/1,218.11 = 487.47/x
  3. Step 3: Cross multiply
    811.87x = 1,218.11 × 487.47
  4. Step 4: Simplify right side
    811.87x = 593,792.08
  5. Step 5: Solve for x
    x = 593,792.08/811.87
  6. Step 6: Final answer
    x = 731.39

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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.