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Finding the Fourth Proportional to 129.66, 178.91 and 77.19

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Solution

The fourth proportional to 129.66, 178.91 and 77.19 is: 106.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    129.66 : 178.91 = 77.19 : x
  2. Step 2: Convert to fraction form
    129.66/178.91 = 77.19/x
  3. Step 3: Cross multiply
    129.66x = 178.91 × 77.19
  4. Step 4: Simplify right side
    129.66x = 13,810.06
  5. Step 5: Solve for x
    x = 13,810.06/129.66
  6. Step 6: Final answer
    x = 106.51

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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.