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Finding the Fourth Proportional to 129.67, 178.95 and 71.45

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Solution

The fourth proportional to 129.67, 178.95 and 71.45 is: 98.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    129.67 : 178.95 = 71.45 : x
  2. Step 2: Convert to fraction form
    129.67/178.95 = 71.45/x
  3. Step 3: Cross multiply
    129.67x = 178.95 × 71.45
  4. Step 4: Simplify right side
    129.67x = 12,785.98
  5. Step 5: Solve for x
    x = 12,785.98/129.67
  6. Step 6: Final answer
    x = 98.60

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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.