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Finding the Fourth Proportional to 90.86, 135.54 and 84.38

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Solution

The fourth proportional to 90.86, 135.54 and 84.38 is: 125.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.86 : 135.54 = 84.38 : x
  2. Step 2: Convert to fraction form
    90.86/135.54 = 84.38/x
  3. Step 3: Cross multiply
    90.86x = 135.54 × 84.38
  4. Step 4: Simplify right side
    90.86x = 11,436.19
  5. Step 5: Solve for x
    x = 11,436.19/90.86
  6. Step 6: Final answer
    x = 125.87

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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.