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Finding the Fourth Proportional to 72.10, 99.66 and 66.43

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Solution

The fourth proportional to 72.10, 99.66 and 66.43 is: 91.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    72.10 : 99.66 = 66.43 : x
  2. Step 2: Convert to fraction form
    72.10/99.66 = 66.43/x
  3. Step 3: Cross multiply
    72.10x = 99.66 × 66.43
  4. Step 4: Simplify right side
    72.10x = 6,620.41
  5. Step 5: Solve for x
    x = 6,620.41/72.10
  6. Step 6: Final answer
    x = 91.82

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.