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Finding the Fourth Proportional to 91.12, 136.40 and 66.68

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Solution

The fourth proportional to 91.12, 136.40 and 66.68 is: 99.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    91.12 : 136.40 = 66.68 : x
  2. Step 2: Convert to fraction form
    91.12/136.40 = 66.68/x
  3. Step 3: Cross multiply
    91.12x = 136.40 × 66.68
  4. Step 4: Simplify right side
    91.12x = 9,095.15
  5. Step 5: Solve for x
    x = 9,095.15/91.12
  6. Step 6: Final answer
    x = 99.82

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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.