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Finding the Fourth Proportional to 719.78, 1,079.86 and 257.61

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Solution

The fourth proportional to 719.78, 1,079.86 and 257.61 is: 386.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    719.78 : 1,079.86 = 257.61 : x
  2. Step 2: Convert to fraction form
    719.78/1,079.86 = 257.61/x
  3. Step 3: Cross multiply
    719.78x = 1,079.86 × 257.61
  4. Step 4: Simplify right side
    719.78x = 278,182.73
  5. Step 5: Solve for x
    x = 278,182.73/719.78
  6. Step 6: Final answer
    x = 386.48

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.