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Finding the Fourth Proportional to 126.60, 189.81 and 72.60

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Solution

The fourth proportional to 126.60, 189.81 and 72.60 is: 108.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    126.60 : 189.81 = 72.60 : x
  2. Step 2: Convert to fraction form
    126.60/189.81 = 72.60/x
  3. Step 3: Cross multiply
    126.60x = 189.81 × 72.60
  4. Step 4: Simplify right side
    126.60x = 13,780.21
  5. Step 5: Solve for x
    x = 13,780.21/126.60
  6. Step 6: Final answer
    x = 108.85

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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.