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Finding the Fourth Proportional to 811.69, 1,217.94 and 378.79

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Solution

The fourth proportional to 811.69, 1,217.94 and 378.79 is: 568.37

Step by Step Solution

  1. Step 1: Write the proportion equation
    811.69 : 1,217.94 = 378.79 : x
  2. Step 2: Convert to fraction form
    811.69/1,217.94 = 378.79/x
  3. Step 3: Cross multiply
    811.69x = 1,217.94 × 378.79
  4. Step 4: Simplify right side
    811.69x = 461,343.49
  5. Step 5: Solve for x
    x = 461,343.49/811.69
  6. Step 6: Final answer
    x = 568.37

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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.