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Finding the Fourth Proportional to 120.40, 166.15 and 71.29

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Solution

The fourth proportional to 120.40, 166.15 and 71.29 is: 98.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    120.40 : 166.15 = 71.29 : x
  2. Step 2: Convert to fraction form
    120.40/166.15 = 71.29/x
  3. Step 3: Cross multiply
    120.40x = 166.15 × 71.29
  4. Step 4: Simplify right side
    120.40x = 11,844.83
  5. Step 5: Solve for x
    x = 11,844.83/120.40
  6. Step 6: Final answer
    x = 98.38

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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.