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Finding the Fourth Proportional to 92.91, 128.32 and 72.12

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Solution

The fourth proportional to 92.91, 128.32 and 72.12 is: 99.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    92.91 : 128.32 = 72.12 : x
  2. Step 2: Convert to fraction form
    92.91/128.32 = 72.12/x
  3. Step 3: Cross multiply
    92.91x = 128.32 × 72.12
  4. Step 4: Simplify right side
    92.91x = 9,254.74
  5. Step 5: Solve for x
    x = 9,254.74/92.91
  6. Step 6: Final answer
    x = 99.61

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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.