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Finding the Fourth Proportional to 129.50, 194.39 and 78.18

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Solution

The fourth proportional to 129.50, 194.39 and 78.18 is: 117.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    129.50 : 194.39 = 78.18 : x
  2. Step 2: Convert to fraction form
    129.50/194.39 = 78.18/x
  3. Step 3: Cross multiply
    129.50x = 194.39 × 78.18
  4. Step 4: Simplify right side
    129.50x = 15,197.41
  5. Step 5: Solve for x
    x = 15,197.41/129.50
  6. Step 6: Final answer
    x = 117.35

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.