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Finding the Fourth Proportional to 86.94, 129.94 and 68.72

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Solution

The fourth proportional to 86.94, 129.94 and 68.72 is: 102.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.94 : 129.94 = 68.72 : x
  2. Step 2: Convert to fraction form
    86.94/129.94 = 68.72/x
  3. Step 3: Cross multiply
    86.94x = 129.94 × 68.72
  4. Step 4: Simplify right side
    86.94x = 8,928.66
  5. Step 5: Solve for x
    x = 8,928.66/86.94
  6. Step 6: Final answer
    x = 102.70

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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.