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Finding the Fourth Proportional to 124.72, 186.70 and 81.30

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Solution

The fourth proportional to 124.72, 186.70 and 81.30 is: 121.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    124.72 : 186.70 = 81.30 : x
  2. Step 2: Convert to fraction form
    124.72/186.70 = 81.30/x
  3. Step 3: Cross multiply
    124.72x = 186.70 × 81.30
  4. Step 4: Simplify right side
    124.72x = 15,178.71
  5. Step 5: Solve for x
    x = 15,178.71/124.72
  6. Step 6: Final answer
    x = 121.70

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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.