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Finding the Fourth Proportional to 821.70, 1,233 and 388.86

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Solution

The fourth proportional to 821.70, 1,233 and 388.86 is: 583.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    821.70 : 1,233 = 388.86 : x
  2. Step 2: Convert to fraction form
    821.70/1,233 = 388.86/x
  3. Step 3: Cross multiply
    821.70x = 1,233 × 388.86
  4. Step 4: Simplify right side
    821.70x = 479,464.38
  5. Step 5: Solve for x
    x = 479,464.38/821.70
  6. Step 6: Final answer
    x = 583.50

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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.