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Finding the Fourth Proportional to 120.42, 166.14 and 81.54

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Solution

The fourth proportional to 120.42, 166.14 and 81.54 is: 112.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    120.42 : 166.14 = 81.54 : x
  2. Step 2: Convert to fraction form
    120.42/166.14 = 81.54/x
  3. Step 3: Cross multiply
    120.42x = 166.14 × 81.54
  4. Step 4: Simplify right side
    120.42x = 13,547.06
  5. Step 5: Solve for x
    x = 13,547.06/120.42
  6. Step 6: Final answer
    x = 112.50

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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.