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Finding the Fourth Proportional to 129.51, 178.72 and 79.70

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Solution

The fourth proportional to 129.51, 178.72 and 79.70 is: 109.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    129.51 : 178.72 = 79.70 : x
  2. Step 2: Convert to fraction form
    129.51/178.72 = 79.70/x
  3. Step 3: Cross multiply
    129.51x = 178.72 × 79.70
  4. Step 4: Simplify right side
    129.51x = 14,243.98
  5. Step 5: Solve for x
    x = 14,243.98/129.51
  6. Step 6: Final answer
    x = 109.98

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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.