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Finding the Fourth Proportional to 91.89, 137.85 and 90.43

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Solution

The fourth proportional to 91.89, 137.85 and 90.43 is: 135.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    91.89 : 137.85 = 90.43 : x
  2. Step 2: Convert to fraction form
    91.89/137.85 = 90.43/x
  3. Step 3: Cross multiply
    91.89x = 137.85 × 90.43
  4. Step 4: Simplify right side
    91.89x = 12,465.78
  5. Step 5: Solve for x
    x = 12,465.78/91.89
  6. Step 6: Final answer
    x = 135.66

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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.