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Finding the Fourth Proportional to 102.90, 141.86 and 81.02

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Solution

The fourth proportional to 102.90, 141.86 and 81.02 is: 111.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    102.90 : 141.86 = 81.02 : x
  2. Step 2: Convert to fraction form
    102.90/141.86 = 81.02/x
  3. Step 3: Cross multiply
    102.90x = 141.86 × 81.02
  4. Step 4: Simplify right side
    102.90x = 11,493.50
  5. Step 5: Solve for x
    x = 11,493.50/102.90
  6. Step 6: Final answer
    x = 111.70

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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.