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Finding the Fourth Proportional to 66.67, 91.40 and 65.45

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Solution

The fourth proportional to 66.67, 91.40 and 65.45 is: 89.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    66.67 : 91.40 = 65.45 : x
  2. Step 2: Convert to fraction form
    66.67/91.40 = 65.45/x
  3. Step 3: Cross multiply
    66.67x = 91.40 × 65.45
  4. Step 4: Simplify right side
    66.67x = 5,982.40
  5. Step 5: Solve for x
    x = 5,982.40/66.67
  6. Step 6: Final answer
    x = 89.73

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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.