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Finding the Fourth Proportional to 129.40, 178.18 and 109.76

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Solution

The fourth proportional to 129.40, 178.18 and 109.76 is: 151.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    129.40 : 178.18 = 109.76 : x
  2. Step 2: Convert to fraction form
    129.40/178.18 = 109.76/x
  3. Step 3: Cross multiply
    129.40x = 178.18 × 109.76
  4. Step 4: Simplify right side
    129.40x = 19,555.87
  5. Step 5: Solve for x
    x = 19,555.87/129.40
  6. Step 6: Final answer
    x = 151.13

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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.