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Finding the Fourth Proportional to 85.47, 128.03 and 66.18

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Solution

The fourth proportional to 85.47, 128.03 and 66.18 is: 99.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.47 : 128.03 = 66.18 : x
  2. Step 2: Convert to fraction form
    85.47/128.03 = 66.18/x
  3. Step 3: Cross multiply
    85.47x = 128.03 × 66.18
  4. Step 4: Simplify right side
    85.47x = 8,472.69
  5. Step 5: Solve for x
    x = 8,472.69/85.47
  6. Step 6: Final answer
    x = 99.13

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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.