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Finding the Fourth Proportional to 811.74, 1,218.15 and 378.93

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Solution

The fourth proportional to 811.74, 1,218.15 and 378.93 is: 568.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    811.74 : 1,218.15 = 378.93 : x
  2. Step 2: Convert to fraction form
    811.74/1,218.15 = 378.93/x
  3. Step 3: Cross multiply
    811.74x = 1,218.15 × 378.93
  4. Step 4: Simplify right side
    811.74x = 461,593.58
  5. Step 5: Solve for x
    x = 461,593.58/811.74
  6. Step 6: Final answer
    x = 568.65

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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.