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Finding the Fourth Proportional to 821.60, 1,231.98 and 388.52

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Solution

The fourth proportional to 821.60, 1,231.98 and 388.52 is: 582.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    821.60 : 1,231.98 = 388.52 : x
  2. Step 2: Convert to fraction form
    821.60/1,231.98 = 388.52/x
  3. Step 3: Cross multiply
    821.60x = 1,231.98 × 388.52
  4. Step 4: Simplify right side
    821.60x = 478,648.87
  5. Step 5: Solve for x
    x = 478,648.87/821.60
  6. Step 6: Final answer
    x = 582.58

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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.