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Finding the Fourth Proportional to 102.81, 141.78 and 76.89

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Solution

The fourth proportional to 102.81, 141.78 and 76.89 is: 106.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    102.81 : 141.78 = 76.89 : x
  2. Step 2: Convert to fraction form
    102.81/141.78 = 76.89/x
  3. Step 3: Cross multiply
    102.81x = 141.78 × 76.89
  4. Step 4: Simplify right side
    102.81x = 10,901.46
  5. Step 5: Solve for x
    x = 10,901.46/102.81
  6. Step 6: Final answer
    x = 106.04

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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.