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Finding the Fourth Proportional to 820.76, 1,231.66 and 387.94

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Solution

The fourth proportional to 820.76, 1,231.66 and 387.94 is: 582.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    820.76 : 1,231.66 = 387.94 : x
  2. Step 2: Convert to fraction form
    820.76/1,231.66 = 387.94/x
  3. Step 3: Cross multiply
    820.76x = 1,231.66 × 387.94
  4. Step 4: Simplify right side
    820.76x = 477,810.18
  5. Step 5: Solve for x
    x = 477,810.18/820.76
  6. Step 6: Final answer
    x = 582.16

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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.