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Finding the Fourth Proportional to 91.28, 136.88 and 77.90

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Solution

The fourth proportional to 91.28, 136.88 and 77.90 is: 116.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    91.28 : 136.88 = 77.90 : x
  2. Step 2: Convert to fraction form
    91.28/136.88 = 77.90/x
  3. Step 3: Cross multiply
    91.28x = 136.88 × 77.90
  4. Step 4: Simplify right side
    91.28x = 10,662.95
  5. Step 5: Solve for x
    x = 10,662.95/91.28
  6. Step 6: Final answer
    x = 116.82

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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.