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Finding the Fourth Proportional to 129.87, 179.21 and 71.65

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Solution

The fourth proportional to 129.87, 179.21 and 71.65 is: 98.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    129.87 : 179.21 = 71.65 : x
  2. Step 2: Convert to fraction form
    129.87/179.21 = 71.65/x
  3. Step 3: Cross multiply
    129.87x = 179.21 × 71.65
  4. Step 4: Simplify right side
    129.87x = 12,840.80
  5. Step 5: Solve for x
    x = 12,840.80/129.87
  6. Step 6: Final answer
    x = 98.87

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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.