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Finding the Fourth Proportional to 85.52, 128.39 and 56.66

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Solution

The fourth proportional to 85.52, 128.39 and 56.66 is: 85.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.52 : 128.39 = 56.66 : x
  2. Step 2: Convert to fraction form
    85.52/128.39 = 56.66/x
  3. Step 3: Cross multiply
    85.52x = 128.39 × 56.66
  4. Step 4: Simplify right side
    85.52x = 7,273.65
  5. Step 5: Solve for x
    x = 7,273.65/85.52
  6. Step 6: Final answer
    x = 85.05

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.