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Finding the Fourth Proportional to 825.86, 1,139.59 and 489.71

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Solution

The fourth proportional to 825.86, 1,139.59 and 489.71 is: 675.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    825.86 : 1,139.59 = 489.71 : x
  2. Step 2: Convert to fraction form
    825.86/1,139.59 = 489.71/x
  3. Step 3: Cross multiply
    825.86x = 1,139.59 × 489.71
  4. Step 4: Simplify right side
    825.86x = 558,060.47
  5. Step 5: Solve for x
    x = 558,060.47/825.86
  6. Step 6: Final answer
    x = 675.74

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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.