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Finding the Fourth Proportional to 119.88, 165.38 and 81

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Solution

The fourth proportional to 119.88, 165.38 and 81 is: 111.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    119.88 : 165.38 = 81 : x
  2. Step 2: Convert to fraction form
    119.88/165.38 = 81/x
  3. Step 3: Cross multiply
    119.88x = 165.38 × 81
  4. Step 4: Simplify right side
    119.88x = 13,395.38
  5. Step 5: Solve for x
    x = 13,395.38/119.88
  6. Step 6: Final answer
    x = 111.74

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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.