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Finding the Fourth Proportional to 439.78, 659.72 and 115.15

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Solution

The fourth proportional to 439.78, 659.72 and 115.15 is: 172.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    439.78 : 659.72 = 115.15 : x
  2. Step 2: Convert to fraction form
    439.78/659.72 = 115.15/x
  3. Step 3: Cross multiply
    439.78x = 659.72 × 115.15
  4. Step 4: Simplify right side
    439.78x = 75,966.76
  5. Step 5: Solve for x
    x = 75,966.76/439.78
  6. Step 6: Final answer
    x = 172.74

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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.