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Finding the Fourth Proportional to 86.90, 129.73 and 68.84

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Solution

The fourth proportional to 86.90, 129.73 and 68.84 is: 102.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.90 : 129.73 = 68.84 : x
  2. Step 2: Convert to fraction form
    86.90/129.73 = 68.84/x
  3. Step 3: Cross multiply
    86.90x = 129.73 × 68.84
  4. Step 4: Simplify right side
    86.90x = 8,930.61
  5. Step 5: Solve for x
    x = 8,930.61/86.90
  6. Step 6: Final answer
    x = 102.77

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.