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Finding the Fourth Proportional to 129.55, 178.75 and 74.29

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Solution

The fourth proportional to 129.55, 178.75 and 74.29 is: 102.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    129.55 : 178.75 = 74.29 : x
  2. Step 2: Convert to fraction form
    129.55/178.75 = 74.29/x
  3. Step 3: Cross multiply
    129.55x = 178.75 × 74.29
  4. Step 4: Simplify right side
    129.55x = 13,279.34
  5. Step 5: Solve for x
    x = 13,279.34/129.55
  6. Step 6: Final answer
    x = 102.50

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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.