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Finding the Fourth Proportional to 839.12, 1,157.98 and 489.80

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Solution

The fourth proportional to 839.12, 1,157.98 and 489.80 is: 675.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    839.12 : 1,157.98 = 489.80 : x
  2. Step 2: Convert to fraction form
    839.12/1,157.98 = 489.80/x
  3. Step 3: Cross multiply
    839.12x = 1,157.98 × 489.80
  4. Step 4: Simplify right side
    839.12x = 567,178.60
  5. Step 5: Solve for x
    x = 567,178.60/839.12
  6. Step 6: Final answer
    x = 675.92

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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.