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Finding the Fourth Proportional to 91.11, 135.73 and 86.43

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Solution

The fourth proportional to 91.11, 135.73 and 86.43 is: 128.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    91.11 : 135.73 = 86.43 : x
  2. Step 2: Convert to fraction form
    91.11/135.73 = 86.43/x
  3. Step 3: Cross multiply
    91.11x = 135.73 × 86.43
  4. Step 4: Simplify right side
    91.11x = 11,730.93
  5. Step 5: Solve for x
    x = 11,730.93/91.11
  6. Step 6: Final answer
    x = 128.76

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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.