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Finding the Fourth Proportional to 72.64, 109 and 66.83

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Solution

The fourth proportional to 72.64, 109 and 66.83 is: 100.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    72.64 : 109 = 66.83 : x
  2. Step 2: Convert to fraction form
    72.64/109 = 66.83/x
  3. Step 3: Cross multiply
    72.64x = 109 × 66.83
  4. Step 4: Simplify right side
    72.64x = 7,284.47
  5. Step 5: Solve for x
    x = 7,284.47/72.64
  6. Step 6: Final answer
    x = 100.28

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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.