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Finding the Fourth Proportional to 86.60, 129.75 and 72.07

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Solution

The fourth proportional to 86.60, 129.75 and 72.07 is: 107.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.60 : 129.75 = 72.07 : x
  2. Step 2: Convert to fraction form
    86.60/129.75 = 72.07/x
  3. Step 3: Cross multiply
    86.60x = 129.75 × 72.07
  4. Step 4: Simplify right side
    86.60x = 9,351.08
  5. Step 5: Solve for x
    x = 9,351.08/86.60
  6. Step 6: Final answer
    x = 107.98

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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.