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Finding the Fourth Proportional to 386.34, 579.66 and 139.57

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Solution

The fourth proportional to 386.34, 579.66 and 139.57 is: 209.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    386.34 : 579.66 = 139.57 : x
  2. Step 2: Convert to fraction form
    386.34/579.66 = 139.57/x
  3. Step 3: Cross multiply
    386.34x = 579.66 × 139.57
  4. Step 4: Simplify right side
    386.34x = 80,905.22
  5. Step 5: Solve for x
    x = 80,905.22/386.34
  6. Step 6: Final answer
    x = 209.42

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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.