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Finding the Fourth Proportional to 91.15, 125.81 and 54.31

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Solution

The fourth proportional to 91.15, 125.81 and 54.31 is: 74.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    91.15 : 125.81 = 54.31 : x
  2. Step 2: Convert to fraction form
    91.15/125.81 = 54.31/x
  3. Step 3: Cross multiply
    91.15x = 125.81 × 54.31
  4. Step 4: Simplify right side
    91.15x = 6,832.74
  5. Step 5: Solve for x
    x = 6,832.74/91.15
  6. Step 6: Final answer
    x = 74.96

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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.