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Finding the Fourth Proportional to 92.91, 128.18 and 57.90

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Solution

The fourth proportional to 92.91, 128.18 and 57.90 is: 79.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    92.91 : 128.18 = 57.90 : x
  2. Step 2: Convert to fraction form
    92.91/128.18 = 57.90/x
  3. Step 3: Cross multiply
    92.91x = 128.18 × 57.90
  4. Step 4: Simplify right side
    92.91x = 7,421.33
  5. Step 5: Solve for x
    x = 7,421.33/92.91
  6. Step 6: Final answer
    x = 79.88

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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.