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Finding the Fourth Proportional to 85.28, 117.60 and 66.88

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Solution

The fourth proportional to 85.28, 117.60 and 66.88 is: 92.23

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.28 : 117.60 = 66.88 : x
  2. Step 2: Convert to fraction form
    85.28/117.60 = 66.88/x
  3. Step 3: Cross multiply
    85.28x = 117.60 × 66.88
  4. Step 4: Simplify right side
    85.28x = 7,865.09
  5. Step 5: Solve for x
    x = 7,865.09/85.28
  6. Step 6: Final answer
    x = 92.23

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.