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Finding the Fourth Proportional to 111.79, 154.20 and 85.66

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Solution

The fourth proportional to 111.79, 154.20 and 85.66 is: 118.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    111.79 : 154.20 = 85.66 : x
  2. Step 2: Convert to fraction form
    111.79/154.20 = 85.66/x
  3. Step 3: Cross multiply
    111.79x = 154.20 × 85.66
  4. Step 4: Simplify right side
    111.79x = 13,208.77
  5. Step 5: Solve for x
    x = 13,208.77/111.79
  6. Step 6: Final answer
    x = 118.16

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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.