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Finding the Fourth Proportional to 135.39, 186.85 and 86.31

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Solution

The fourth proportional to 135.39, 186.85 and 86.31 is: 119.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    135.39 : 186.85 = 86.31 : x
  2. Step 2: Convert to fraction form
    135.39/186.85 = 86.31/x
  3. Step 3: Cross multiply
    135.39x = 186.85 × 86.31
  4. Step 4: Simplify right side
    135.39x = 16,127.02
  5. Step 5: Solve for x
    x = 16,127.02/135.39
  6. Step 6: Final answer
    x = 119.12

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.