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Finding the Fourth Proportional to 85.89, 128.65 and 57.03

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Solution

The fourth proportional to 85.89, 128.65 and 57.03 is: 85.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.89 : 128.65 = 57.03 : x
  2. Step 2: Convert to fraction form
    85.89/128.65 = 57.03/x
  3. Step 3: Cross multiply
    85.89x = 128.65 × 57.03
  4. Step 4: Simplify right side
    85.89x = 7,336.91
  5. Step 5: Solve for x
    x = 7,336.91/85.89
  6. Step 6: Final answer
    x = 85.42

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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.