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Finding the Fourth Proportional to 821.07, 1,231.59 and 388.53

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Solution

The fourth proportional to 821.07, 1,231.59 and 388.53 is: 582.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    821.07 : 1,231.59 = 388.53 : x
  2. Step 2: Convert to fraction form
    821.07/1,231.59 = 388.53/x
  3. Step 3: Cross multiply
    821.07x = 1,231.59 × 388.53
  4. Step 4: Simplify right side
    821.07x = 478,509.66
  5. Step 5: Solve for x
    x = 478,509.66/821.07
  6. Step 6: Final answer
    x = 582.79

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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.