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Finding the Fourth Proportional to 821.34, 1,133.78 and 489.70

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Solution

The fourth proportional to 821.34, 1,133.78 and 489.70 is: 675.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    821.34 : 1,133.78 = 489.70 : x
  2. Step 2: Convert to fraction form
    821.34/1,133.78 = 489.70/x
  3. Step 3: Cross multiply
    821.34x = 1,133.78 × 489.70
  4. Step 4: Simplify right side
    821.34x = 555,212.07
  5. Step 5: Solve for x
    x = 555,212.07/821.34
  6. Step 6: Final answer
    x = 675.98

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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.