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Finding the Fourth Proportional to 67.28, 91.89 and 66.69

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Solution

The fourth proportional to 67.28, 91.89 and 66.69 is: 91.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    67.28 : 91.89 = 66.69 : x
  2. Step 2: Convert to fraction form
    67.28/91.89 = 66.69/x
  3. Step 3: Cross multiply
    67.28x = 91.89 × 66.69
  4. Step 4: Simplify right side
    67.28x = 6,128.14
  5. Step 5: Solve for x
    x = 6,128.14/67.28
  6. Step 6: Final answer
    x = 91.09

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.