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Finding the Fourth Proportional to 85.04, 128.10 and 80.79

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Solution

The fourth proportional to 85.04, 128.10 and 80.79 is: 121.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.04 : 128.10 = 80.79 : x
  2. Step 2: Convert to fraction form
    85.04/128.10 = 80.79/x
  3. Step 3: Cross multiply
    85.04x = 128.10 × 80.79
  4. Step 4: Simplify right side
    85.04x = 10,349.20
  5. Step 5: Solve for x
    x = 10,349.20/85.04
  6. Step 6: Final answer
    x = 121.71

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.