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Finding the Fourth Proportional to 811.96, 1,218.39 and 379.11

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Solution

The fourth proportional to 811.96, 1,218.39 and 379.11 is: 568.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    811.96 : 1,218.39 = 379.11 : x
  2. Step 2: Convert to fraction form
    811.96/1,218.39 = 379.11/x
  3. Step 3: Cross multiply
    811.96x = 1,218.39 × 379.11
  4. Step 4: Simplify right side
    811.96x = 461,903.83
  5. Step 5: Solve for x
    x = 461,903.83/811.96
  6. Step 6: Final answer
    x = 568.88

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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.