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Finding the Fourth Proportional to 86.72, 129.26 and 86.58

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Solution

The fourth proportional to 86.72, 129.26 and 86.58 is: 129.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.72 : 129.26 = 86.58 : x
  2. Step 2: Convert to fraction form
    86.72/129.26 = 86.58/x
  3. Step 3: Cross multiply
    86.72x = 129.26 × 86.58
  4. Step 4: Simplify right side
    86.72x = 11,190.90
  5. Step 5: Solve for x
    x = 11,190.90/86.72
  6. Step 6: Final answer
    x = 129.05

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.