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Finding the Fourth Proportional to 811.54, 1,217.72 and 378.62

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Solution

The fourth proportional to 811.54, 1,217.72 and 378.62 is: 568.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    811.54 : 1,217.72 = 378.62 : x
  2. Step 2: Convert to fraction form
    811.54/1,217.72 = 378.62/x
  3. Step 3: Cross multiply
    811.54x = 1,217.72 × 378.62
  4. Step 4: Simplify right side
    811.54x = 461,053.15
  5. Step 5: Solve for x
    x = 461,053.15/811.54
  6. Step 6: Final answer
    x = 568.12

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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.