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Finding the Fourth Proportional to 138.30, 189.80 and 124.40

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Solution

The fourth proportional to 138.30, 189.80 and 124.40 is: 170.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.30 : 189.80 = 124.40 : x
  2. Step 2: Convert to fraction form
    138.30/189.80 = 124.40/x
  3. Step 3: Cross multiply
    138.30x = 189.80 × 124.40
  4. Step 4: Simplify right side
    138.30x = 23,609.55
  5. Step 5: Solve for x
    x = 23,609.55/138.30
  6. Step 6: Final answer
    x = 170.71

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.