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Finding the Fourth Proportional to 129.09, 177.90 and 87.62

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Solution

The fourth proportional to 129.09, 177.90 and 87.62 is: 120.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    129.09 : 177.90 = 87.62 : x
  2. Step 2: Convert to fraction form
    129.09/177.90 = 87.62/x
  3. Step 3: Cross multiply
    129.09x = 177.90 × 87.62
  4. Step 4: Simplify right side
    129.09x = 15,586.38
  5. Step 5: Solve for x
    x = 15,586.38/129.09
  6. Step 6: Final answer
    x = 120.74

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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.