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Finding the Fourth Proportional to 91.32, 136.20 and 89.91

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Solution

The fourth proportional to 91.32, 136.20 and 89.91 is: 134.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    91.32 : 136.20 = 89.91 : x
  2. Step 2: Convert to fraction form
    91.32/136.20 = 89.91/x
  3. Step 3: Cross multiply
    91.32x = 136.20 × 89.91
  4. Step 4: Simplify right side
    91.32x = 12,245.74
  5. Step 5: Solve for x
    x = 12,245.74/91.32
  6. Step 6: Final answer
    x = 134.10

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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.