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Finding the Fourth Proportional to 129.72, 179 and 77.28

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Solution

The fourth proportional to 129.72, 179 and 77.28 is: 106.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    129.72 : 179 = 77.28 : x
  2. Step 2: Convert to fraction form
    129.72/179 = 77.28/x
  3. Step 3: Cross multiply
    129.72x = 179 × 77.28
  4. Step 4: Simplify right side
    129.72x = 13,833.12
  5. Step 5: Solve for x
    x = 13,833.12/129.72
  6. Step 6: Final answer
    x = 106.64

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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.