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Finding the Fourth Proportional to 92.89, 128.24 and 72.21

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Solution

The fourth proportional to 92.89, 128.24 and 72.21 is: 99.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    92.89 : 128.24 = 72.21 : x
  2. Step 2: Convert to fraction form
    92.89/128.24 = 72.21/x
  3. Step 3: Cross multiply
    92.89x = 128.24 × 72.21
  4. Step 4: Simplify right side
    92.89x = 9,260.21
  5. Step 5: Solve for x
    x = 9,260.21/92.89
  6. Step 6: Final answer
    x = 99.69

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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.