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Finding the Fourth Proportional to 821.43, 1,133.40 and 489.80

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Solution

The fourth proportional to 821.43, 1,133.40 and 489.80 is: 675.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    821.43 : 1,133.40 = 489.80 : x
  2. Step 2: Convert to fraction form
    821.43/1,133.40 = 489.80/x
  3. Step 3: Cross multiply
    821.43x = 1,133.40 × 489.80
  4. Step 4: Simplify right side
    821.43x = 555,133.65
  5. Step 5: Solve for x
    x = 555,133.65/821.43
  6. Step 6: Final answer
    x = 675.81

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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.