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Finding the Fourth Proportional to 386.19, 579.05 and 139.28

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Solution

The fourth proportional to 386.19, 579.05 and 139.28 is: 208.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    386.19 : 579.05 = 139.28 : x
  2. Step 2: Convert to fraction form
    386.19/579.05 = 139.28/x
  3. Step 3: Cross multiply
    386.19x = 579.05 × 139.28
  4. Step 4: Simplify right side
    386.19x = 80,647.01
  5. Step 5: Solve for x
    x = 80,647.01/386.19
  6. Step 6: Final answer
    x = 208.83

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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.