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Finding the Fourth Proportional to 92.80, 128.28 and 85.24

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Solution

The fourth proportional to 92.80, 128.28 and 85.24 is: 117.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    92.80 : 128.28 = 85.24 : x
  2. Step 2: Convert to fraction form
    92.80/128.28 = 85.24/x
  3. Step 3: Cross multiply
    92.80x = 128.28 × 85.24
  4. Step 4: Simplify right side
    92.80x = 10,934.59
  5. Step 5: Solve for x
    x = 10,934.59/92.80
  6. Step 6: Final answer
    x = 117.83

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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.