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Finding the Fourth Proportional to 129.08, 178.19 and 87.77

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Solution

The fourth proportional to 129.08, 178.19 and 87.77 is: 121.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    129.08 : 178.19 = 87.77 : x
  2. Step 2: Convert to fraction form
    129.08/178.19 = 87.77/x
  3. Step 3: Cross multiply
    129.08x = 178.19 × 87.77
  4. Step 4: Simplify right side
    129.08x = 15,640.07
  5. Step 5: Solve for x
    x = 15,640.07/129.08
  6. Step 6: Final answer
    x = 121.16

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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.