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Finding the Fourth Proportional to 86.12, 129.21 and 28.35

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Solution

The fourth proportional to 86.12, 129.21 and 28.35 is: 42.53

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.12 : 129.21 = 28.35 : x
  2. Step 2: Convert to fraction form
    86.12/129.21 = 28.35/x
  3. Step 3: Cross multiply
    86.12x = 129.21 × 28.35
  4. Step 4: Simplify right side
    86.12x = 3,663.05
  5. Step 5: Solve for x
    x = 3,663.05/86.12
  6. Step 6: Final answer
    x = 42.53

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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.