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Finding the Fourth Proportional to 92.79, 128.10 and 61.28

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Solution

The fourth proportional to 92.79, 128.10 and 61.28 is: 84.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    92.79 : 128.10 = 61.28 : x
  2. Step 2: Convert to fraction form
    92.79/128.10 = 61.28/x
  3. Step 3: Cross multiply
    92.79x = 128.10 × 61.28
  4. Step 4: Simplify right side
    92.79x = 7,849.33
  5. Step 5: Solve for x
    x = 7,849.33/92.79
  6. Step 6: Final answer
    x = 84.59

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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.