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Finding the Fourth Proportional to 129.64, 178.90 and 80.51

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Solution

The fourth proportional to 129.64, 178.90 and 80.51 is: 111.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    129.64 : 178.90 = 80.51 : x
  2. Step 2: Convert to fraction form
    129.64/178.90 = 80.51/x
  3. Step 3: Cross multiply
    129.64x = 178.90 × 80.51
  4. Step 4: Simplify right side
    129.64x = 14,402.14
  5. Step 5: Solve for x
    x = 14,402.14/129.64
  6. Step 6: Final answer
    x = 111.10

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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.