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Finding the Fourth Proportional to 386.76, 580.02 and 139.92

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Solution

The fourth proportional to 386.76, 580.02 and 139.92 is: 209.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    386.76 : 580.02 = 139.92 : x
  2. Step 2: Convert to fraction form
    386.76/580.02 = 139.92/x
  3. Step 3: Cross multiply
    386.76x = 580.02 × 139.92
  4. Step 4: Simplify right side
    386.76x = 81,156.40
  5. Step 5: Solve for x
    x = 81,156.40/386.76
  6. Step 6: Final answer
    x = 209.84

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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.