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Finding the Fourth Proportional to 811.83, 1,218.20 and 378.99

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Solution

The fourth proportional to 811.83, 1,218.20 and 378.99 is: 568.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    811.83 : 1,218.20 = 378.99 : x
  2. Step 2: Convert to fraction form
    811.83/1,218.20 = 378.99/x
  3. Step 3: Cross multiply
    811.83x = 1,218.20 × 378.99
  4. Step 4: Simplify right side
    811.83x = 461,677.63
  5. Step 5: Solve for x
    x = 461,677.63/811.83
  6. Step 6: Final answer
    x = 568.69

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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.