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Finding the Fourth Proportional to 386.78, 580.12 and 112.86

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Solution

The fourth proportional to 386.78, 580.12 and 112.86 is: 169.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    386.78 : 580.12 = 112.86 : x
  2. Step 2: Convert to fraction form
    386.78/580.12 = 112.86/x
  3. Step 3: Cross multiply
    386.78x = 580.12 × 112.86
  4. Step 4: Simplify right side
    386.78x = 65,472.06
  5. Step 5: Solve for x
    x = 65,472.06/386.78
  6. Step 6: Final answer
    x = 169.28

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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.