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Finding the Fourth Proportional to 91.40, 137.97 and 90.86

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Solution

The fourth proportional to 91.40, 137.97 and 90.86 is: 137.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    91.40 : 137.97 = 90.86 : x
  2. Step 2: Convert to fraction form
    91.40/137.97 = 90.86/x
  3. Step 3: Cross multiply
    91.40x = 137.97 × 90.86
  4. Step 4: Simplify right side
    91.40x = 12,535.26
  5. Step 5: Solve for x
    x = 12,535.26/91.40
  6. Step 6: Final answer
    x = 137.15

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.