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Finding the Fourth Proportional to 811.62, 1,217.88 and 378.75

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Solution

The fourth proportional to 811.62, 1,217.88 and 378.75 is: 568.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    811.62 : 1,217.88 = 378.75 : x
  2. Step 2: Convert to fraction form
    811.62/1,217.88 = 378.75/x
  3. Step 3: Cross multiply
    811.62x = 1,217.88 × 378.75
  4. Step 4: Simplify right side
    811.62x = 461,272.05
  5. Step 5: Solve for x
    x = 461,272.05/811.62
  6. Step 6: Final answer
    x = 568.33

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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.