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Finding the Fourth Proportional to 91.99, 137.17 and 90.78

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Solution

The fourth proportional to 91.99, 137.17 and 90.78 is: 135.37

Step by Step Solution

  1. Step 1: Write the proportion equation
    91.99 : 137.17 = 90.78 : x
  2. Step 2: Convert to fraction form
    91.99/137.17 = 90.78/x
  3. Step 3: Cross multiply
    91.99x = 137.17 × 90.78
  4. Step 4: Simplify right side
    91.99x = 12,452.29
  5. Step 5: Solve for x
    x = 12,452.29/91.99
  6. Step 6: Final answer
    x = 135.37

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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.