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Finding the Fourth Proportional to 171.20, 236.56 and 138.40

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Solution

The fourth proportional to 171.20, 236.56 and 138.40 is: 191.24

Step by Step Solution

  1. Step 1: Write the proportion equation
    171.20 : 236.56 = 138.40 : x
  2. Step 2: Convert to fraction form
    171.20/236.56 = 138.40/x
  3. Step 3: Cross multiply
    171.20x = 236.56 × 138.40
  4. Step 4: Simplify right side
    171.20x = 32,739.90
  5. Step 5: Solve for x
    x = 32,739.90/171.20
  6. Step 6: Final answer
    x = 191.24

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.