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Finding the Fourth Proportional to 129.63, 194.30 and 78.28

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Solution

The fourth proportional to 129.63, 194.30 and 78.28 is: 117.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    129.63 : 194.30 = 78.28 : x
  2. Step 2: Convert to fraction form
    129.63/194.30 = 78.28/x
  3. Step 3: Cross multiply
    129.63x = 194.30 × 78.28
  4. Step 4: Simplify right side
    129.63x = 15,209.80
  5. Step 5: Solve for x
    x = 15,209.80/129.63
  6. Step 6: Final answer
    x = 117.33

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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.