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Finding the Fourth Proportional to 85.79, 118.31 and 66.12

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Solution

The fourth proportional to 85.79, 118.31 and 66.12 is: 91.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.79 : 118.31 = 66.12 : x
  2. Step 2: Convert to fraction form
    85.79/118.31 = 66.12/x
  3. Step 3: Cross multiply
    85.79x = 118.31 × 66.12
  4. Step 4: Simplify right side
    85.79x = 7,822.33
  5. Step 5: Solve for x
    x = 7,822.33/85.79
  6. Step 6: Final answer
    x = 91.19

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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.