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Finding the Fourth Proportional to 91.84, 137.09 and 77.40

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Solution

The fourth proportional to 91.84, 137.09 and 77.40 is: 115.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    91.84 : 137.09 = 77.40 : x
  2. Step 2: Convert to fraction form
    91.84/137.09 = 77.40/x
  3. Step 3: Cross multiply
    91.84x = 137.09 × 77.40
  4. Step 4: Simplify right side
    91.84x = 10,610.77
  5. Step 5: Solve for x
    x = 10,610.77/91.84
  6. Step 6: Final answer
    x = 115.54

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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.