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Finding the Fourth Proportional to 85.33, 128.09 and 64.09

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Solution

The fourth proportional to 85.33, 128.09 and 64.09 is: 96.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.33 : 128.09 = 64.09 : x
  2. Step 2: Convert to fraction form
    85.33/128.09 = 64.09/x
  3. Step 3: Cross multiply
    85.33x = 128.09 × 64.09
  4. Step 4: Simplify right side
    85.33x = 8,209.29
  5. Step 5: Solve for x
    x = 8,209.29/85.33
  6. Step 6: Final answer
    x = 96.21

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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.