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Finding the Fourth Proportional to 386, 579.10 and 139.22

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Solution

The fourth proportional to 386, 579.10 and 139.22 is: 208.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    386 : 579.10 = 139.22 : x
  2. Step 2: Convert to fraction form
    386/579.10 = 139.22/x
  3. Step 3: Cross multiply
    386x = 579.10 × 139.22
  4. Step 4: Simplify right side
    386x = 80,622.30
  5. Step 5: Solve for x
    x = 80,622.30/386
  6. Step 6: Final answer
    x = 208.87

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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.