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Finding the Fourth Proportional to 91.20, 136.08 and 89.28

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Solution

The fourth proportional to 91.20, 136.08 and 89.28 is: 133.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    91.20 : 136.08 = 89.28 : x
  2. Step 2: Convert to fraction form
    91.20/136.08 = 89.28/x
  3. Step 3: Cross multiply
    91.20x = 136.08 × 89.28
  4. Step 4: Simplify right side
    91.20x = 12,149.22
  5. Step 5: Solve for x
    x = 12,149.22/91.20
  6. Step 6: Final answer
    x = 133.22

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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.