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Finding the Fourth Proportional to 138.72, 191.70 and 124.32

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Solution

The fourth proportional to 138.72, 191.70 and 124.32 is: 171.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.72 : 191.70 = 124.32 : x
  2. Step 2: Convert to fraction form
    138.72/191.70 = 124.32/x
  3. Step 3: Cross multiply
    138.72x = 191.70 × 124.32
  4. Step 4: Simplify right side
    138.72x = 23,832.14
  5. Step 5: Solve for x
    x = 23,832.14/138.72
  6. Step 6: Final answer
    x = 171.80

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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.