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Finding the Fourth Proportional to 821.12, 1,133.31 and 489.74

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Solution

The fourth proportional to 821.12, 1,133.31 and 489.74 is: 675.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    821.12 : 1,133.31 = 489.74 : x
  2. Step 2: Convert to fraction form
    821.12/1,133.31 = 489.74/x
  3. Step 3: Cross multiply
    821.12x = 1,133.31 × 489.74
  4. Step 4: Simplify right side
    821.12x = 555,027.24
  5. Step 5: Solve for x
    x = 555,027.24/821.12
  6. Step 6: Final answer
    x = 675.94

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.