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Finding the Fourth Proportional to 129.11, 178.17 and 70.90

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Solution

The fourth proportional to 129.11, 178.17 and 70.90 is: 97.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    129.11 : 178.17 = 70.90 : x
  2. Step 2: Convert to fraction form
    129.11/178.17 = 70.90/x
  3. Step 3: Cross multiply
    129.11x = 178.17 × 70.90
  4. Step 4: Simplify right side
    129.11x = 12,631.81
  5. Step 5: Solve for x
    x = 12,631.81/129.11
  6. Step 6: Final answer
    x = 97.84

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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.