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Finding the Fourth Proportional to 85.28, 128.00 and 58.31

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Solution

The fourth proportional to 85.28, 128.00 and 58.31 is: 87.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.28 : 128.00 = 58.31 : x
  2. Step 2: Convert to fraction form
    85.28/128.00 = 58.31/x
  3. Step 3: Cross multiply
    85.28x = 128.00 × 58.31
  4. Step 4: Simplify right side
    85.28x = 7,463.19
  5. Step 5: Solve for x
    x = 7,463.19/85.28
  6. Step 6: Final answer
    x = 87.51

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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.