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Finding the Fourth Proportional to 129.67, 178.75 and 85.34

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Solution

The fourth proportional to 129.67, 178.75 and 85.34 is: 117.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    129.67 : 178.75 = 85.34 : x
  2. Step 2: Convert to fraction form
    129.67/178.75 = 85.34/x
  3. Step 3: Cross multiply
    129.67x = 178.75 × 85.34
  4. Step 4: Simplify right side
    129.67x = 15,254.53
  5. Step 5: Solve for x
    x = 15,254.53/129.67
  6. Step 6: Final answer
    x = 117.64

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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.